Now wait guys, its not always safe to say that things have to be outright stated to be true. Now, its well accepted that Laguna is Squalls father and yet, its not out right stated in the game. Its only hinted at. There is no line in the game that says they are father and son. So, as for rajin and Fuujin it can be hinted at without directly being said. They carry a kind of Brother and Sister attitude towards each other. Not only that, but raijin and fuujin (the japanese dieties) are sibilings. So knowing how square uses stuff like that all the time, i would say its safe to assume they are brother and sister. Also, i always kinda say fujin as not being white, but as being pale. Like, maybe albino. But that was always my take on it. Seeing as she had differnent colored eyes and all. Square doesnt usually give charecters red eyes. Not human charecters anyway. The only time i say a charecter with red eyes was with Vincent in FF7. And it was basically clear that he was kidna albino like. So thats the kinda of thing i got from the Fujin's charecter.

Also Fujin is best paired with Quistis. http://www.fanfiction.net/s/355583/1/
This fanfic proves it.