So you people know, there are sometimes pre-release names and actual names. The pre-release names almost always have to do with the game titles, while the actual ones are made much later and are mostly original (ever since they junked the "name them after the titles" rule).
As of now, they ARE Xavier and Yvonne. Those are their placeholder names and they are put there so that the fanbase doesn't have to refer to them with such ambiguous/cumbersome things as "XY female protagonist" and whatnot. As of this moment, they DO posess those two names, and we should refer to them as such, but their names will CHANGE when the game comes out (assuming Game Freak continues the tradition of giving them a "canon name").
