Avro-Arrow
Smash Journeyman
LRAStart Toon Link.
Actually though, I don't have good MU experience since the only Peaches I've played are garbage.
However, I'd assume that trying to get your aerials as low to the ground as possible and dashing out is how you don't get CC dsmashed. Also, dealing with floating seems bad, and Peach with a turnip is annoying. Fortunately, you can punish turnip pulls; unfortunately, Peach can punish that punish on hit. Her edge guards are good on Sonic (big hitboxes, turnips to snipe, easy punishes on missed sweetspots. Sonic has good juggles on Peach and I think baiting reactions/conditioning your opponent with somersaults (side b) in neutral to elicit a reaction (dsmash, dash attack) would prove very helpful, since she'd feel pressured enough to toss something out and then you can swoop in and get a few quick hits in. While she's on a platform be wary of shield drop nairs so mix up your pressure in those scenarios (waveland grabs, shark uairs, spring dair, super secret Sonic tech mixups, etc.).
Actually though, I don't have good MU experience since the only Peaches I've played are garbage.
However, I'd assume that trying to get your aerials as low to the ground as possible and dashing out is how you don't get CC dsmashed. Also, dealing with floating seems bad, and Peach with a turnip is annoying. Fortunately, you can punish turnip pulls; unfortunately, Peach can punish that punish on hit. Her edge guards are good on Sonic (big hitboxes, turnips to snipe, easy punishes on missed sweetspots. Sonic has good juggles on Peach and I think baiting reactions/conditioning your opponent with somersaults (side b) in neutral to elicit a reaction (dsmash, dash attack) would prove very helpful, since she'd feel pressured enough to toss something out and then you can swoop in and get a few quick hits in. While she's on a platform be wary of shield drop nairs so mix up your pressure in those scenarios (waveland grabs, shark uairs, spring dair, super secret Sonic tech mixups, etc.).