But, Raine's last name is Liore. Like Dazlar Bynon said, it says that on her grave, right? I have never heard Raine Leonhart. I'm pretty sure it's Liore, just that I haven't played the game in so long.....
But, what do we know about the practices of who takes what name when ppl get married in the world of FFVIII? Since it's not consistent and I totally know that Squall is their son, I just assume that they have different practices than us.