I have a S or a A on every event but I can't seem 2 beat all star beta any tips or tricks? Does anyone know the exact time I need to get get to get a A or if keeping all your stocks matter?

Keeping your stocks definitely matters a lot

I had a B rank when I had a score in the 3 minutes range. I have an A rank now with a time of 2:59 and I had lost one stock during the event.

The A-rank threshold is somewhere between 3:01 and 3:30.

The best way I've found to clear these events quickly is either using meteor smashes or luring the opponent to a walkoff and tossing them over the side - DK is pretty good at both of these. (For Bowser, just knock him upwards a few times.) Practice on the event and figure out the AI's oddities (Luigi sometimes self-destructs in the pits with Up special, Falco has a hard time aiming his Up special at the left ledge of Sector Z) and character weaknesses (Sandbag's vertical recovery). And when you get to PAC-MAN, just hope for the best. That's all.

Kamehameha has very high knockback, regardless of charge, and the CPU is much less likely to see it coming than a human player. I used those to get past all the All Star events.

Rush them down with Falcon and get easy combos off grabs. They rarely ever tech. and even if they do, punish with Dair to Knee.

I got 2:31 just now doing that. And that's was a pretty sloppy-run. It's possible to kill every character under 10 seconds. Issac, Sandbag, and Luffy are just spam Knees to get them off-stage and punish their recoveries with more Knees.. Bandana Dee doesn't use any ledge options. So once he grabs a ledge, he's just hanging there for a Dair. Spam Dairs on Falco as he never techs, until he's high enough for Dair > Knee to kill. Bowser, Game&Watch, Luigi, and Pac-Man are pretty random, so just try your best to do Uair chains to Knee to kill them early. Pit tricky as the hazards will help him prolong death, but if you're luck, you can do Knee > Dair right at the start and edgeguard from there. Pit tends to just stand there a second or shoot an off-curved arrow.

samus > back throw > down air

Thanks guys for your help I managed to beat it Ichigo F smash was my answer

Pick Samus
Back Throw
Dair
Ez fast stocks

Learn what combos/follow ups you can do with certain grabs.

Also learn to side dodge and tech.

Use Sonic and spam F-throw/B-throw to F-air meteor

git gud.