True, nothing official regarding WizU, but both of Niantic's other games are on both systems and I can probably guess most of WBGames fall into that same boat. There isn't anything that leads me to believe any differently for WizU. BUT, point is still valid, nothing has been said yet officially haha.
App Store rules say that apps have to be released everywhere they became available for pre-register within 90 days. So the moment the App goes into pre-registration that's a clock that starts ticking.