um.... (well, spoiler alert somewhat if you care)
If you ask me Raine and Laguna being Squall's parents are pretty damn obvious after playing the game.
@DarkFang
I dunno what you mean 'bout coincidence. By sorceress I guess you mean the final villain, Ultimecia (or whatever her name was). Edea is also a sorceress, but not the only one. Edea and Cid ran an orphanage were these kids went, including the ff8 main cast (how Squall ended up here is explained above). Later Edea was possessed by the sorceress. I don't remember exactly how it went down, but eventually Cid started the Garden to kill Ultimecia. 'Cause he was the orphanage leader, Squall and the rest were drafted in.
It's a long time since I played the game, thus I might be a bit off, but I think I'm pretty close here.