1) There is no Acadian Expulsion, and thus the Francophone inhabitants of Nova Scotia are not dispersed (mainly to Louisiana)
2) Quebec somehow manages to side with the revolutionaries (either Guy Carleton is somehow killed or Arnold's military expedition succeeds).
The question I ask is what would the effect of three Francophone states (including St. John's Island/PEI) have on the United States. Would they go settle Upper Canada and the St. John River valley without the flood of Loyalists in our world? How would Montréal develop as a relatively easy gateway to the Great Lakes? And how would the presence of three (most-likely) free states affect the balance of power leading up to the Civil War?