One thing to think about is that, if Quebec joins the Revolution, then the Loyalists aren't going to OTL's Canada. This means no English-speaking Eastern Townships, and a greater French-speaking presence in the Ottawa Valley and eastern Ontario. Glen's Dominion of Southern America TL has much of the "northern tier" of the alt-US (OTL's eastern and central Canada, basically) becoming either francophone or bilingual, owing to the lack of United Empire Loyalists, the French-speaking Metis in Manitoba and northern Ontario, and the Northwest Company's dominance of the fur trade (the US pretty much drives the Hudson's Bay Company out of Rupert's Land).
There's also a strong possibility that, with Quebec in the Union, the First Amendment will include freedom of language in addition to speech, religion, etc. This would butterfly away Quebec's language laws in the 20th century, but it would also butterfly away the assimilation pressures that were placed upon French-Canadians in the 19th century, which could lead to an expanded bilingual belt that includes not just more of eastern/northern Ontario and New Brunswick, but also parts of northern New England as well. I was just reading
this article, and Lewiston, Maine was pretty much a bilingual/francophone city in the early 20th century. With an open border between Quebec and New England, there's a good chance that Vermont, New Hampshire, and Maine could have large French-speaking minorities by the present day, on the order of OTL's New Brunswick.
A question mark, though, is Montreal. I can easily see it replacing New York as the economic/financial center of TTL's US, or at least becoming a rival to it, what with the St. Lawrence River being competitive with the Erie Canal as a route to the Midwest. Montreal could easily develop a large English-speaking minority as it becomes a center of commerce.