Mom's into BDSM, youngest daughter is the exhibitionist/multiple partner. Middle daughter is the bad girl, who hates you, likely the most corruptible. Oldest daughter is the saint, likely going to be the most fun to corrupt. Her boyfriend though, I can't wait to kick their ass.
The bright side of this situation is save for the middle sister the rest it will be a strictly relationship building game, while it may move quickly I think the storyline needs a little kink to entice people into investing in the game.