You don't need to use any of them, and you can change anything about them. The hair styles are just to go with the outfits. You don't need to use them if you use one of the outfits. So the first one is obviously based on Mimikyu. The second one is what I think of when I think of ghost type. The third one is more towards Mimikyu being a Ghost and Fairy type. The light pink parts are supposed to be see through
