No, probably not the pig form.
As for what we need him to do- we don't know that yet. We don't have the mechanics of the fight, we need to accept a boss entry first, laying out the battle flow and stuff. So if I were you, Spritonic, I could just hold off on the battle animations until we know what he'll do in the battle's he's involved in (final boss as well as fighting the Sheikah alongside Link). Also, he reveals himself as Ganondorf, the evil king from legends, at some point, and we need to decide if this will necessitate an appearance change. And, for that matter, if he will go by a pseudonym before he reveals his identity.
One idea we could do- he wears some sort of basic disguise he tosses aside at the end- a scarf that covers some of his face, a helmet, a poncho type thing, a billowing cape, robes, whatever. Then when he reveals that he is the demon thief, Ganondorf, he can just take this off and reveal that he's been wearing the typical Ganondorf clothes from Ocarina of Time or Wind Waker or whatever.
Another idea is that, like, Sheik, he uses magic to disguise himself, having a different Skin color maybe, and uses magic at the end to transform into the typical, recognizable Ganondorf we all expect to battle. I like the actual disguise better, but this could work too.
And then yeah, would he use a fake name when he's pretending to be a new Gerudo king interested in peace?