Grandmothers hypothesis(spoilers)
We know that:
1-Fang and Vanille were on crystal form which means they are very old but they appearance didnīt change.
2-Many humans from Pulse went to Cocoon after it was created.
It is therefore possible that Fang and Vanilleīs husbands decided to depart against their will and even get divorced.Alongside with their child.
Vanille was not much young when she turned to crystal either.
Her age probably was enough to marry on Gran Pulse and have children.
They may not remember that either.
Judging from the character interactions and personalities I would say
that Fang is Claire and Serahīs grandmother.And Vanille is Noraīs mother.
Whether they are grandmother or grandgrand mother depend on many factors.
He's probably still trying to link this game to FFVIII
rotfl..
Gee how may threads can someone start with one hypothesis..reads guess..after another...:roll2
Final Fantasy XIII - Wikipedia, the free encyclopedia