WHOOPS Nvm

You don't need to use all of Sonic's afterimages to go under the stage. I honestly don't know the exact movements to take to make sure I get it perfect every time.
So for now I can only get it right 1/10th of the time.

I've got lots of hope
Stay hopeful

Hey, I know bounce>bair is the better option most of the time, but for times when you're fighting peach, jiggs, or kirby, could it be possible for bounce>uair to kill earlier? This is assuming you landed the bounce right on top of them and are in line to follow up with the uair.
(spindash shorthop>uair kills peach at 91% with bad di)
EDIT:
-bounce>uair kills peach at 81% with bad di
-bounce>bair kills peach at 110% from center stage with bad di

I mean hey, it's interesting to know and would be cool to try out

It looks like you already tested it out. I'll try it out for myself.

How about f-air to homing attack?

I don't think that fair has a huge amount of hitstun to do something like that.

Not the best option because of low hitstun afterward, but is useful offstage at times.
ninja'd

Thinking of maybe f-air to light speed attack?

Dude noo, fair doesn't have enough hitstun and I don't think it sends you at the right angle even if it did.

Spindash>Spring>Bounce Attack>F-Throw

How about you test these combos out yourself.

But hey, it works^{against a CPU, set to Stand, on a flat stage, at the exact right percent, maybe}

In all seriousness, up-B is impractical in combos, even with the "pillar". Perhaps you should try dspec -> nair, as that keeps you near the opponent.

A lot of people forget that Smash has platforming elements.
Sonic can duck or spindash to avoid Samus's rocket and even the kameha wave if you're on a slightly lower platform.

I know this is kind of impractical, but a lot of the time when me and my opponent are running towards each other, I just run past them and they attack while i'm actually behind them.
This tactic honestly shouldn't work, but it does. But if you're fighting a character with long lasting attacks like Wario rush or falcon kick, then you shouldn't do it.

Run past opponent>shorthop bair is among sonic players' most used kill options and general attack options, and falcon kick is mostly unviable anyway so you shouldn't expect to see it much.
Also, fullhop over opponent>bair works way more times than it should, especially if you haven't done it the whole match
(Conditioning)

Dear God, I'm horrible at combo ideas.