Dang that's difficult.. I can't choose an overall most attractive but Leon, Ada, and carlos are at top for me.

Ada Wong, Michaela (BERTHA), Karena (LUPO) and Christine (FOUR EYES). All from Resident Evil. Alcina Dimitrescu is also something else. Yes, I'm a Resident Evil guy

Outside of Resident Evil, I would say Chun-Li from Street Fighter and Lady from Devil May Cry

This is a hard one, but I would probably say Tiffany from rival schools