Ohhh, I'll play!

1. I would say Lae'zel or even Minthara can sacrifice you in a sex ritual.

2. Turning you into a Vampire would be Astarion but that would only happen by helping him become a true vampire. (Hence you are his mind and body)

3. I can see marriage with the rest such as Gale, Shadowheart, Karlach and Halsin.