Have you considered territorial expansion of Newfoundland?
Say for example Quebec secedes, but the Cree/Inuit in the north don't want to go along, and Newfoundland somehow wins them over instead of them staying in Canada or joining Quebec. Possible reasons being Newfoundland is small enough that their small population would allow for better representation, or a land connection with the rest of Canada would be severed by an independent Quebec.
From there the Inuit self rule movement could end with the Arctic archipelago acceding to Newfoundland rather than the creation of Nunavut. After that, Greenland would join.
The US would certainly be in favour of this, considering the Newfoundland you have thus far is even more in America's influence that Canada was OTL, and having the Arctic in Newfoundlander hands would be a boon for the US. They might even build a deep water port like Canada has always
wanted to do but never had the funds for.
So Großnewfoundland would look this:
I painted the Maritimes red but in that timeline what happens to them is anyone's guess.