Scale this Master Hand down just a little bit, derive most of his moves from the WoL minigame, though made somewhat more reasonable. Make him a super-heavy, maybe slightly heavier than Bowser. While grounded, he floats slightly and his jumps, he has two, are rather high but also stupendiously slow and floaty. When being launched, he hits the ground on his backside before pulling himself up, like his animations for getting stunned and recovering from said stun.
Tinfoil time, but the lack of a proper, unlockable mode for the existing minigame is so damn criminal, seemingly such an oversight... your post actually has me seeing this as... almost more likely than not. That's messed up.