Wii Party U Miis
So... here's the thing.
Look, I'll just be honest with you: I can't find these Miis ANYWHERE in the game files. Trust me, I've looked everywhere. I seriously can't find them.
However, I can find the text file that lists all the names of the Miis, meaning I at least know which ones definitely are in (and it's the ones you guessed).
I will continue searching for the Mii data files in this game, as there very well could be some unused Miis I don't know about. Until then, here are the Miis that definitely are in the game.