>>6992628>>6992716We know that in the toy story world within the kh universe, that sroa and company are fictional characters from a video game series at the least. Thus it is a reasonable assumption that their toy form looks like what they do in the game.
Also interviews with Pixar in regards to working with squenix led to this little trivia. They were initially having trouble communicating with the Japanese designers about the feel and soul that should be in the toy story world. So they asked them a simple question, 'what toys did you grow up playing with and what do you feel when remembering them?' this got the Japanese team to realize the whole point of the nostalgia of toys in toy story and led to the inclusion of giant Mecha toys that can be piloted.
I think it's safe to assume that Sora and company got their toy design as a result of the Japanese toy nostalgia. Or maybe it's better to assume that since final fantasy appears as a toy line in the toy store that squenix has themselves exist in the toy story world and they made the in universe game that Sora appears in.