TIME FOR AN ULTRA DUMP OF DATA I GUESS (Except frame data)
Also, i have no idea if i actually finished gathering information, as i may have very well missed a thing or another
EDIT: Yep, I knew i was forgetting something, added a little extra info on the Down Special section

• Up Smash
While the hitbox doesn't quite cover his sides, it lingers for quite a bit and his low traction can make up for the lack of horizontal range by doing the move out of a dash
Another thing some people may or may not know, is that the move has a sweetspot on Waluigi's head at the peak of his jump
The sweetspot deals 16%, and both sourspots deal 11% ^{(The late hit also has slightly less knockback than the early hit)}

• Forward Smash
It's pretty decent, but the angle makes it difficult to actually get a KO when the opponent knows where to DI
It does reflect projectiles though, but it's not as reliable as Mario Cape or even shielding depending on the situation ^{(No damage multiplier either, now i wonder if there are any plans on making certain reflectors increase the strength of reflected projectiles)}

• Down Smash
Ah, what else are you useful for, other than stringing into UpB?...
Well, it hits below the ledge against certain characters and covers a few ledge options (may trade with certain ledge getup attacks though).... i guess.. Oh, and it reaches above platforms at the end.
After a little more testing, the move pulls shielding opponents towards Waluigi, and pretty much will alway catch them if they try to roll or grab ^{(Spot dodge lets them avoid it at first, but if done too early then they will still get caught in the move)}
Because of how quickly the move can multihit, most opponents will be forced to shield throughout the entire move before getting to punish Waluigi, which will somewhat deplete their shield ^{(no stupid shield damage like Peach's or Sheik's DSmash even if charged though)}



• Neutral Tilt Jab
Jab-1 has set knockback, sending the opponent slightly upwards which prevents them from being able to react before the next hit, and it's quick enough for you to use his Forward-Tilt or Up-Tilt before or right when the opponent tries to get away ^{(Up-Tilt is faster but has less horizontal range, and FTilt may catch them and will send them offstage)}.
DSmash is also an option, but won't catch the opponent if they simply jump away
if the opponent is on the ledge and DIs towards the arena on the second hit, they will very likely be set up for a spike or FAir

• Down Tilt
Don't use it.. it's just.. it's not bad but it's too specific to be very useful, this move is more like a taunt attempting to be an attack.
Anyways, the third stomp doesn't tumble opponents until past 100%, but this may actually be good as you cannot meteor cancel or tech out of a flinch, making this "pseudo-spike" very dangerous for fastfallers on the ledge
If an opponent is grounded when the third stomp hits, it will always tumble them even at 0% in a similar manner to Luigi's down taunt when hitting onstage (except it has knockback growth), which can let you use it to confirm a few close-range attacks, unfortunately the first and second stomp will also lift the opponent into the air slightly, which heavily limits the third stomp's ability to "trip" opponents.
Still, despite this, the move is too specific to be of much help

• Forward Tilt
The move has a sweetspot on Waluigi's fingers ^{(or more specifically on the "sparkle" effect)}, though it doesn't make all that much of a difference, just +1% damage and slightly more knockback.

The "tipper" hitbox CAN poke through depleted shields, but i wouldn't rely on it.

• Up Tilt
Now we're talking, This will likely will be your most used tilt, be it for damage or for possible kill confirms.
The directions where the opponent can DI makes them either go almost straight up, or go right behind Waluigi
Here are some setups you can do: Up-Tilt (one or several depending on percentage) into sweetspotted Up-Smash, or UpB if they don't DI behind Waluigi, or any of his Aerials if you want to rack up more damage rather than go for the kill
The "test subject" for these was Mario in Training Mode. Staleness and different characters will obviously change things around

- At percentages until ~100% it can confirm an Up-Smash sweetspot, if the opponent DIs behind Waluigi ^{(which is likely to happen when pressured on the ledge)}, the "maximum percentage" this setup can work increases by roughly 25%, though Waluigi will have to dash backward and Up-Smash before the opponent gets to jump away. Conveniently his Up-Smash sweetspot can KO once past 100%.
- Once around 100% or over the 130%'s ^{(depending whether it was from a single up-tilt, or from 2 up-tilts)}, the move can confirm the UpB sweetspot, but only works when the opponent doesn't DI behind Waluigi.


• Forward Aerial
Honestly, that is one janky move, depending on your spacing this can deal 6%, 9%, 12%, or 15%.
An early hit on Waluigi's foot/leg will deal 12%, and it seems that the next frame the same hitboxes then deal 9% (with the 15% sweetspot also showing up, which seems to take priority over the "sourspot"?..), and the late hit deals 6%. The 15% sweetspot is basically whenever Waluigi's foot is directly in front of him

Even though it's the weakest sourspot, the late hit still has its uses as it reaches above platforms and can be used to catch your opponents offguard, and its horribly low knockback actually makes it useful as a sort of surprise kill-confirm
The move also chains into itself very easily, letting him rack up an absurd amount of damage with one quick FAir string at low percentages, though the drawback is that this will obviously stale the move.
The even jankier thing about this however, is that staleness ironically makes the move more "powerful" by taking away its kill power and turning it into a combo tool.

• Back Aerial
The move has a sweetspot and a sourspot - The sourspot is at Waluigi's legs and it deals 10% damage, The sweetspot is at his feet, dealing 13% and higher knockback, with slightly misleading hitboxes both for where does it sweetspot on his feet and on how much range it has

• Up Aerial
Ah yes, the move that made everyone freak out and go in an uproar when we all first saw this..
I think we already know enough about this move that i don't think i can even really say much about it other than that it's pretty good at catching opponents trying to recover from high up
The first hitbox that drags you towards the second hit comes out frame 5, and the spike hitbox comes out on frame 7 ^{(without including the hitlag from connecting the first hitbox)}
Also, the first hit doesn't link very reliably into the spike hitbox - you can land the first hit but can still whiff the spike if you're fastfalling or moving away from the opponent ^{(unlike Sonic's up-air, where the first hit's knockback also uses his momentum to determine the angle and strength so it reliably connects with the second hitbox)}
Plus, because it's an "Upwards Aerial Spike", you can use this during recovering to surprise opponents if they are edgeguarding too close to the edge (heavily depends on spacing and/or DI on whether they simply "trip" onto the ground or fall to their doom)

• Down Aerial
Pretty much ultimate G&W's DAir but without a landing hitbox - a Stall-Then-Fall with a strong spike at the first active frame of the move, but throws the opponent at high angle with weaker strength otherwise, do NOT use this offstage if you aren't above ledge height, and do NOT press down during the move when offstage because you will fall even faster ^{(his fastfall speed is faster than his DAir fastfall)}.
his DAir is a viable alternative to his up-air when the opponent is below him, the spike comes out 2 frames faster (at frame 5 instead of 7), has stronger knockback and sends slightly more forwards instead of straight down, you still have to be precise with it though.

• Neutral Aerial
I honestly haven't used it all too much, but as far as i've seen, it covers a very wide horizontal area (but stretches Waluigi's hurtbox like he's secretly Mewtwo), like any NAir, it is a decent approach option (when not against disjoints) and can be used to confirm a few attacks depending on the opponent DI, and the late hit is just as good as any late NAir with the possible kill confirms at higher percentages
My guess is that you would use this aerial mostly for when you aren't sure of the opponent's DI and movement, as his NAir has very wide range and the hitboxes linger for a good amount of time
couple this with his insane fast-falling speed and his NAir can look pretty intimidating ^{(and feel more like a new and wacky as hell DAir)}


• Grab
Nothin' much to say of course, so instead have his approximate grab range
Reaches quite forward and also covers somewhat around him (until like on his leg at the front, as it seems)

• Throws
In general, Waluigi seems to generally lack decent kill throws (up-throw is okay against floaties, and FThrow may kill fastfallers, but the DI angle still makes it less than optimal), making him rely on his Piranha Plant to make up for his less-than-optimal throws

Instead of "talking" about the throws, i'll just simply show their DI angles in GIFs
As you can see, with bad DI his back/forward throw are actually pretty good, so if possible you may want to find a way to surprise your opponent into doing bad DI's with mindgames

Time for his specials, oh boy..

• Neutral Special
Ah yes, the waluigi dice... it's kind of underwhelming to be honest as it can't actually kill without 5's confirm or a 6, though 2 can easily cheese most recoveries. The dice's effect is very easily outprioritized by almost any move, so unless you land a 2 when an opponent is attacking, their moves will very likely outprioritize the hitbox and will be left unscathed ^{(6 has higher priority, but a strong enough attack will still outprioritize it)}

Anyways, let's get onto his dice numbers:
[1] - Deals 2% and causes the opponent to flinch, with knockback identical to Luigi's UpB sourspot

[2] - Deals no damage, instead pushes the opponent with a strong windbox that cannot be interrupted/countered by any non-reflector move
Because of how this is instead a windbox and it cannot clank with other attacks, Dice-2 is a very powerful edgeguard since it doesn't put the opponent out of their helpless state.

[3] - Deals no damage initially (Marth cannot use Counter on it) and has set knockback (only slightly stronger than Dice-1), but poisons the opponent for a total of 12% damage, with 1% every 10 frames (which means the poison effect lasts for 4 seconds)

[4] - Deals 5% and stuns the opponent in place for 20 frames, deals very low knockback (identical to Pika/chu's thunder jolts)

[5] - Deals 8% and, depending whether the opponent is on the ground or mid-air, will respectively bury or spike them (the spike is not particularly strong though)

[6] - Deals a whopping 20% with decent priority and very strong knockback. In terms of the knockback's strength, it's comparable to something between Samus' charge shot and Donkey Kong's giant punch

There are a few tricks you can do with the Dice - First, being a "bouncing" projectile, it can bounce off of walls, which include the sides of platforms, and it won't count towards how many times can the dice bounce on the ground ^{(it bounces once on the ground, and reveals a number when hitting the ground again)}
Secondly, if you throw the dice with near perfect vertical spacing, it will instead slide across the arena/platform (Platforms are much easier) instead of bouncing, giving it much more range than normal


• Side Special
As mentioned by Dust, it has six "phases" determined by how many times the purple circles close in on Waluigi's body, with the fifth one being his "Misfire", which deals a nice 15% and decently strong knockback (KO'ing around the 100%'s on average), though nowhere as powerful as Luigi's.

The sixth phase however is identical to the move coming out completely uncharged, dealing 9% and very low knockback
Curiously, the fourth phase also goes faster (and therefore further) than his fifth phase's Misfire
The second big difference compared to Luigi's version, is that Waluigi can only use this move once until he either lands on the ground or gets hit
And last, but not least - he will home in on the closest opponent that is in his way, whether you like it or not, as you have no control of where Waluigi goes and there seems to be no limit to the distance betweem him and his opponent.
He will not home in on the opponent if they're behind him, or if there is a wall/floor/ceiling in the path ^{(platforms don't get in the way)}


• Up Special
Basically Luigi's UpB, but with the hitboxes in reverse: the move will only sweetspot at the last active frame (which is when he poses), but sourspot at any other point before this ^{(though there's a small window where there are no hitboxes near the end, to prevent the sweetspot from needing TAS-like precision)}
One would probably think his sweetspot is insanely small like jigglypuff rest or something, since when you hit the opponent too early and Waluigi does the pose while still right on top of them, it won't sweetspot

This means that the best way to sweetspot Waluigi's UpB, is to face away from the opponent, as the hitbox covers much more distance behind Waluigi than in front/around
It's almost as powerful as Luigi's UpB, but its angle makes it KO later than Luigi's with optimal DI.
Regardless, because of how the move functions, you will pretty much almost always sweetspot it high the air, which more than makes up for its lower angle and slightly weaker knockback

• Down Special
PLANT GANG! PLANT GANG! PLANT GANG!
Ahem.. the Piranha Plant will very likely be your most used special for all sorts of situations, especially kill confirms.
Waluigi will put down a plant pot (or drop it mid-air, à la Pac-Man's hydrant) and after a short moment on the ground, Thaddeus "Chompers" DePlant will sprout from the pot and "guard" the area around him.

The plant will despawn after: biting and throwing an opponent; failing to grab the opponent up to 5 times in a row ^{(each failed grab seems to slightly decrease its timer)}; after approximately 8 seconds of nothing happening after the "sprouting" animation; After being attacked by the opponent with a non-projectile move ^{(15% damage to despawn if projectile or teammate)}; or if Waluigi himself uses his Jab on the plant ^{(Which gives it a faster despawn animation})
Another thing i recently found out is that the projectile MUST deal knockback in order to kill Piranha Plant, so Mario's cape or Fox' blaster are unable to kill it

Anyways, it'll bite and sink its teeth into any opponent that wanders too close to it, then throw them backwards, forwards, or upwards depending on Waluigi position at the moment of the bite (moving around after the bite won't change its throw direction)

You can also use it as a leaf shield ^{(megaman joke intended)} against all non-piercing projectiles or use it as a ledge trap against recoveries without large hitboxes

The most common thing you will be doing with his Piranha Plant is to use Waluigi's attacks (most notably down throw) to throw the opponent into it and confirm a variety of moves for as soon as they get launched back
Alternatively, you can make some really stylish combos involving the plant

Another thing you can do is to have Piranha Plant close to Waluigi as he grabs an opponent, in which case it will repeatedly bite the opponent up to 5 times and add up a lot of damage to Waluigi's pummels ^{(If the opponent escapes from Waluigi's grasp, chances are the plant will immediately grab & throw them right afterwards)}
The higher the percentage, the more rewarding this setup becomes as it takes longer for the opponent to be able to mash out
Oh, i almost forgot! If you start the move mid-air and touch the ground, you will still be able to move left/right, which is much better than doing the move grounded as you won't be standing still

EDIT: How could i forget?! The plant pot has a hitbox when it's mid-air, and you cannot "destroy" it or even do anything about it, giving it some potential in escaping juggles, "claiming" the ledge for yourself when recovering from above, or simply covering some of the opponent's movement options
You can use it in similar vein to Pac-Man's hydrant - drop it offstage and you can get some disrespectful KO's

I really hope you find a place to continue dumping data even after the forums close because this is so insane. I love it

I found something out!
If piranha plant gets hit by a projectile (Including Waluigi Dice, but strangely does not work in training mode) after biting someone, it won't despawn!

This! You're doing god's work, Craft.

My, oh my, At least we have Discord, so i guess i'll just do what i already do (write everything down in a notepad, minus BBCode, then post everything once i'm done)
While the forums are definitely much more organized, it seems that in Discord i can put more/better information as there are many more people who probably know a few more things than i do (I have the knowledge, but they have the skill)

I wonder if i have enough time for another data dump on another character... I think i know who's next...