I feel as if it were a new region it would have to mean "new Pokemon." Unless you mean to make it like say "new islands" appears off the wester coast of Kalos. Or they somehow plan to travel to the "new region" but end up getting sucked into another deminsion instead (which would lead the to believe it's the new region).

Including Looker in some way sound really interesting though! Yeah coming up with an idea that just fits is tough.