I'd almost want an alias instead. There's less clutter that way, and I wouldn't think it'd be too much to weed through the human characters (who, if anything, fall under alternate_costume instead) to find the "shiny" Pokemanz.
If it's an established in-universe concept for the Pokemon games I don't necessarily have a problem using it. Pokemon is an enormous tag so helping break it down isn't too bad. Done.
