Pokemon X+Y Scoop of the Century! MegaEvolution's and More! My prediction became true :-)

[Aielyn]

I think a Hoenn connection is likely, actually. But not because of the sorts of details mentioned in the OP.

Rather, I look at the map, and notice something. Bodies of water. Or rather, lack of large bodies of water. Also lack of any hot area (volcano). These were the two features that were key in Hoenn. Also notice that the most recent ad for the game shows off some underwater battling, which implies the return of Dive (as a full-fledged feature) - which is odd, since there doesn't appear to be much by way of areas you'd expect to be diving into on the map.

Recall that Hoenn was meant to be a fair distance from Kanto/Johto, while it's fairly strongly implied that Sinnoh is somewhat close to them. I could easily see Hoenn being to the west of Kalos.