I didn't have Pixie appear in Marin's second event - Rinny appeared for me, which I'm guessing might be why I can't do anything with Pixie.
Thats because you have Rinny before doing the event and tell her do leave when you enter Marin's room.
If you want Pixie appear don't bring Rinny to do Marin's event (left her in the succubus tower).
