I have not done it for the others yet, but I think I understand how. It's similar to how I figured out how the game handles the music files. It'll be tedious, but I feel it'll be good to jumpstart this so people can dive in when they're ready. I'm working on getting extra costume slots to load for everyone as well.
Well this certainly caught my attention. Has anyone been able to make custom textures for costumes? Like say a purple Robin or something similar to that?