Simon: Jace; cause he's stronger and a fellow shadowhunter for you.

Magnus: Alec; cause he can be very friendly with those he cares about.

Jace: Alec or Clary; because of how close you are with them.

Isabelle: Simon; you two are always together.

Clary: Jace; He is hot,strong and charming.

Alec: Magnus or Izzy; they can get any body and make most swoon by just a wink.