Personally, I'd do Mimikyu like this: Disguise would work as "Reduced damage until X%" X here being, I don't know, let's say 100. After that, it's more of an "All Bets Are Off" type of situation, where Mimikyu gets faster, but now takes regular damage. Discarding Disguise at a low threshold is a little incongruous. I mean, it's flimsy already, but Mimikyu's going to be a little hands-on, so maybe the disguise'll be more battle-ready.
I liked Feint Attack as the Up special, though perhaps it launches a bit at the junctures. Play Rough seems like it'd still be a command grab (Neutral special), but more of one where the animation is instead a large cloud, like the ones in old cartoons (the hitbox is the cloud). Perhaps the Down special should be Will o' Wisp, a sort of "trap" move that Mimikyu can set up to hinder approaches. Side special should be Double Team: a spectral copy is sent out, then return to Mimikyu, doing more damage at the endpoints. Shadow Claw, instead, could take the form of the regular grabs: an enormous spectral claw that comes out of Mimikyu's Disguise and crushes those it catches, then throws them out. It's also a tether grab.
Side Smash is a Wood Hammer using its "tail". Up Smash is sort of an "Astonish" situation, where it's the exclamation point (Not sure on this one, send critiques). Down Smash is a bunch of ghostly spikes jutting out of the ground - their purpose is more to stun the surrounding opponents, sort of like an electric shock, but with spectral energy.
Of course, Final Smash is "Let's Snuggle Forever", which is a cinematic.