CONFIRMED by the Pokémon Company. At certain points in the game we'll be able to get new accessories and outfits for our protagonists. We'll be able to go back and change our outfits whenever we like. Also, since the new camera angles show our characters close up and in detail, we'll be able to see their new outfits on them.
So, it looks like we won't only be able to just change skin color, eye color, and hair color after all!