so, yeah, we've been playing this the last couple of days and it's pretty fun : D you were totally right about it needing stocks. there's just really no other way to do it feasibly and have it be fun.
in the end we allowed:
ganon, falcon, bowser, zss: down b only
sonic, mk, ivy, wario: down air only
fox, falco, wolf, lucario: up b, but has to be angled down somehow
bowser was just trash, poor guy : ( zss is pretty tricky, since she's one of two characters who can kick behind her, but her setup's super slow, so she's mid tier at best. ganon's too slow, buti n ffa's, he can get a lot of random kills with his shockwave and some good timing. sonic's a beast, since he's so fast he can punish things super easy. mk is like a combo of zss and sonic, with SO MANY JUMPS, the ability to pseudo kick behind him (needing to jump first), and anglable kick, and good ground speed. we thought he might be too good, then we met the terror that is ivysaur's uair... i think we decided she wasn't allowed anymore on our last game of the night.
surprisingly, space animals upb isn't so good (wolf's being notably faster to startup, though, was great). the ability to go through platforms was really good for them, though.
i'd really like to find a way to have stock-stamina for this, so we can give big characters more hits or something, though. think that might make it more even. #pipedream
that's my smash dive kick metagame writeup : p