The Dolls are really interesting characters and tie into the story really well. Juni & Juli were in Alpha 3. Decapre was in Ultra Street Fighter IV and there's mumbling that Satsuki, Marz or both of them are going to be in season 2 of Street Fighter V.
They're both copies of Data East's Karate Champ. They tried suing Capcom over the first Street Fighter but the judge ruled you can't copyright the "idea" behind a game and threw it out of court.
Yep, and that's hilarious because Capcom sued Data East tit-for-tat over Fighter's History for the same reason, losing that suit for essentially trying to copyright the whole genre.