For adding Miis to Miitopia, it has an online feature like that Wii Channel where you can search for a name and it will show you Miis tagged with that name. I had people like Zelda, Inking, Layton, Captain Falcon. Sometimes it will let you choose and other times it will just bring in popular Miis. Pewdiepie, Trump, Sakurai and multiple Marios are in my game because of this. It does let you change characters to a different Mii if you get something you dont like.
I really liked Miitopia, I hope at least Gui tries it for the show.