In the name of "what if", and because we *STILL* don't have an opening date for Uncharted, I had a look on Maps, and - surprisingly - there's more space around Mexico than I thought.
If they want a European WWoHP (I still have reservations given behind the scenes clashes within Universal that are ongoing regarding the Author) they could pretty much drop in USO's version (Minus Hagrid's) with little problem. It would be a bit "shoehorned" given the main pathway would cross between Hogsmeade and Forbidden Journey, but for crowd flow, anyone entering from the China side would still go directly through Hogsmeade.
El Diablo and some smaller rides would be removed, and the railway would be rerouted. In Pink is where you could add a Hogsmeade station, but this would only be to service the existing train rather than a Hogwarts Express attraction.
I wouldn't be at all surprised if Universal do acquire PA. And if they do, they aren't exactly strangers to rides in compact places, thanks to USH. Super Nintendo World is designed to cram in basically anywhere, and Polynesia has been crying out for a coaster akin to Velocicoaster or Flying Dinosaur.
It would certainly shake up the European industry. Many are coining Universal's expansion plans as the "Universal Decade" - lets not forget the "Disney Decade" brought us DLP