Considering that the Kingdom Hearts HD collection is using the Final Mix version as a basis, I think it seems very likely that this will be based on the International version.

That being said, I'm perfectly happy with my original PS2 copy so I probably won't be getting this when/if it comes out. Playing it in widescreen with crispy HD graphics is a nice idea, but I'm probably not going to get the same game twice unless there's some kind of bonus that I need to have. Or if I ever got a Vita and I'm dying to play some FFX on the go.