I think Persona 4 was actually set to be a PS3 game, until it was later changed to be a PS2 game. So, I personally think the programmers were actually working on developing an engine for a PS3 game while the other part of the team were working on Persona 4. With that, I think now they are ready to shift into HD with the first phase of development being completed, and in this case it would most likely be on PS3. But there's a possibility of an SMT spin-off for Wii.
It's actually hard to say anything concrete about Kingdom Hearts 3 for now, except that I personally think there will be a spin-off KH game on Wii soon, similar to Birth by Sleep on PSP in terms of graphics.
I think there is a high possibility for KH3 game to be released on PS3 (and Xbox 360 in west), because Square Enix have already created a great HD engine, and seeing how Nomura is working on a massive game like Versus XIII, you would think that it wouldn't be that hard to develop KH3 for PS3 by that time.







