Primarily a falcon player, a scrub none the less, I'll give the falcon write-up a try.
This is an honest to god david vs. goliath matchup. You've got low-tier pichu, who's character is the size of c. Falcon's head, vs. Mr. Powermove himself, capt. falcon. For pichu, the trick to this is keeping in that magic zone where falcon can't shff knee you, and he can't get a running sh fair. Approach with caution, and use your nimble size to avoid grabs and get on the offense if capt. tries to approach with an aerial. Keep on your toes. It's important to remember that he's faster than you. If he goes for a combo, use di/your small size to get out of folow-up range, which shouldn't be a problem at higher percents, due to the fact that he'll knock you the hell out of follow-up range.
This is the most important thing for light characters to remember when facing falcon: Avoid the knee like the god**** plague. Space yourself and brace yourself. If you get off the stage, you've got about a 60% chance of recovery. He's going to wallhop, bair, fair, and edge-hog his behind off, and edgeguard like the dickens. In case I wasn't being clear earlier, don't just avoid the knee, avoid anything that could get you off the stage. I mean Fsmashes, dsmashes, usmashes, dairs, bairs, and even the gentleman. You may not see it coming, but he's going to follow up. I promise.
Finally, as for grabs, coming from capt. Falcon, they shouldn't be much trouble. Above %50, they're going to have trouble getting a steady follow-up if you di/try to not get hit, really.
Just an extra word of advice: Falcon's gonna mindgame you. His character is perfect for it. You being at an offensive disadvantage, you're going to need to play the smarter game. just wavedash, don't get pivot-fsmashed, and try to get your juggle going before he can get at you.
Sorry if this doesn't help, this is from more of a defensive perspective for pichu. Happy smashing.
