1.Terra is half what?
Half human, half Esper.
2.Sabin and Edgar had a coin toss to see who would have control of there.....
Over Figaro/the Kingdom/The throne/ Whatever or their freedom. Edgar won the toss and he was the king of Figaro from then on. Sabin, however, left and trained in martial arts.
3.What is Shadow's true name?
Claude or Clyde . . . sumth'n like that.
4.Cyan lost his family to...
Kefka, after Kefka poisoned Doma Castle's water in defyance of General Leo.