I'm gad you're enjoying the game :) To answer your questions:
1. Sword Girl and Quiet Girl will return in Act Three, and their mysteries solved (if you maxed out college Authority)
2. Yup!
3. Possibly. It's a vestigial stat so I'll either build on it/rework it or drop it :P
4. There's a couple "subtle" anal scenes already but there will be a lot more in Act Three :)
Hope that answers everything!