Sister of course
What's a summoner again? O.o Or is that Lyon's class...?
I voted for Sage, Druid, Bishop and Necromancer. It's funny how Sages and Druids receive the magic type that their main type of magic is strong against. I guess it's just "logical" (logic is rather rare/non-existant in Fire Emblem) since dark magic + light magic = ? and same goes for innocent Sages learning dark arts that make people go crazy.