By final you mean the third one? If so, you can buy Bowsette #3 and Pocahontas #3 from Aika in the academy. Just open the map, head into the academy and buy them from Aika.
You need to win a minigame in Morisawa’s residence (also available in the map), if you cannot see the location yet, it'll be unlocked later on in the story (Episode 5).
