→ ring a bell
It's a good question, but it might lead to something. Least is shows that this N Episode might be more than just a Chronicle like special.
Anyways, maybe not Hoenn but there is always the Sinnoh/Johto "Battle Frontier". Wherever they wanna put it. And in the matter of Caitlin being part of the Elite Four of Unova that can easily be covered since it's her Butler that is really the frontier brain? iirc... But not really fond of this idea because he would be backtracking a bit?
But honestly I really like the idea of a Plasma arc. :|b Maybe the place Axew ends up in is a lead up to it if we don't have information on where Axew ends up in yet. idk.