I can't imagine XV-2 and KH4 (if that releases in this generation) not being multiplatform. While the games will naturally do significantly worse on Xbox One, it probably can't cost SE that much to port them, especially after the hard work has already been done once with their predecessors. So unless XV and KH3 completely and utterly tanks on Xbox One the system should be getting the follow-ups.
Now Sony could choose to go the Microsoft route of buying temporary exclusivity, since this is SE we're talking about, but I don't see why they would do that. It doesn't seem like them at all, and I don't think it would really do them any good. It'd anger the few Xbox fans there are and it probably wouldn't lead to an increase in sales.
If Type-0 and XV/KH3 will make any difference to Xbox One fans, it'll be with future spin-offs and other smaller SE franchises. For example, if Type-0 really does as poorly on Xbox One as the anecdotal evidence points towards, that'd probably be a small enough fry that I wouldn't be completely surprised if whatever "Type-Next" is might end up as a PS4 exclusive. It's still far from a given, though.