Actually, we have no proof whatsoever that the girl on the beach is Kairi. And as for Squall's age- they made him older in Kingdom Hearts so he isn't 17. He looks more like 21 already- and that would make him 25 in KH2 if your theory is correct. I really don't like the idea of making them older. A year or two I wouldn't care about, but the girl that you think is Kairi is an adult- completely redesigned. I would miss her short hair! I'm hoping that the KH2 preview is just a rough brainstorm result and that they put more thought into the actual designing of the game and its characters. Don't get me wrong- the two keyblade idea is cool, but I'm hoping that girl isn't Kairi and that it's Tifa or someone else.