Is Nova Scotia were to get another QMJHL team, it would have to be Truro.
In New Brunswick you can't really go to Fredericton unless they get some deal with UNB worked out which seems really unlikely.
Other options (albeit really small) would be either Edmunston (16,032 in city, 21,442 in metro) or Miramichi(17,811 pop in city, 28,115 in metro) both of which are bigger than Bathurst, and Edmunston is on the road to Quebec. Though, I'm not sure aside from the small population what other challenges they'd face.
Aside from those two places, the Kennebecasis Valley has the population but is basically a part of Saint John, and there is Dieppe which is basically Moncton.
I think it is unlikely NB gets an expansion, probably Truro if anywhere in the Maritimes. And I don't know if the Q would try NFLD again, especially with the AHL still there for a few more years. When Montreal moves St.John's to Laval as I've heard rumors of, then perhaps they might try again?