Squall - Rinoa. I can't see Squall with anyone else, except for Seifer in a completely different context.
Selphie - Irvine. Irvine and not Zell, because I thought Selphie and Irvine had better chemistry. Zell and Squall seemed more like big brothers to Selphie. Plus in the ending video Selphie is wearing a cowgirl hat, which matches well with Irvine's cowboy outfit.
Zell - random school girl.
Quistis - Seifer. Quistis is serious, quiet, strong, and smart. Seifer is loud, sort of obnoxious, and impulsive. It never could have worked between Squall and Quistis, and Seifer and Quistis just look good together.
Raijin - Fujin
Edea - Cid. I could be mistaken, but wasn't Cid with Edea in the ending footage?