It can't be Edea though...Since
She took care of all the main chracters while they were at the Orphanage.
Let's see....*crosses off Adel, Edea, Ellone, among the more obvious wrong answers*
Actually, I can't figure it out.

I was going to say that singing chick, but then again, she hooked up with Laguna, and is no doubt Squall's mother.