I'm still taking the position that if you buy a game, you own it and are able to do as you wish. If you own dissidia and FF7PC, then you can put dissidia characters into FF7PC and vice versa if you have the tools/know how. If you want to show off what you've done because you're proud of it, do so. If you want to make your own models or textures to put in a game you own, also ok. If you want to make a tutorial so other people may follow suit, it's still ok.
It's when you DISTRIBUTE that material to people who have not paid for said game that it becomes a legal issue. I realize it's kind of dull around here, but we really need to get away from all the unnecessary overreaction to double posts and bickering and pictures of dissidia models. The heavy handedness tends to drive people away from qhimm.com