Welcome to Gaia! ::

My Theories:

Ganon - will return. 3nodding Of course... but I don't think he'll be a clone of Captain Falcon, and he might actually use that big b*****d sword of his.

Young Link - will return as well, in the cel-shaded style of Wind Waker. His special moves will be different than adult Link's, and he will use tools from Wind Waker and other games of that art style, such as perhaps the Deku Leaf, the Fire Rod, and other classical Zelda tools.

Sheik - will return...? I'm not so sure... but I think there's a pretty good chance that Zelda will still be able to turn into Sheik. Nothing has been confirmed yet, though....

Vaati - has a good chance of being playable... if he is playable, he will be in his humanoid form like he was in Minish Cap. If he is not playable, he could be a boss in Adventure Mode in his big, globular one-eyed form.

Midna - will be an Assist Trophy... she comes soooo close to being playable, but she doesn't quite have enough history or potential attacks... so she would probably appear as an Assist Trophy to aid her caller with one of her abilities with her dextrous braid.