If Quebec holds in 1759, then the British will probably try again later until peace comes, and it will remain the focus of the NA theatre. As long as the French hold Quebec, they can launch raids into NE and against occupied Acadia....
Regiments from NA that went into the Caribbean subsequent to the fall will not be available. the Caribbean campaign against the Islands and Havana is delayed and or weaker.
Even if Quebec fell later in 1760/61. the French may hold more of their Caribbean possessions at the peace and Havana may not have been captured
Spain keeps Florida.... France keeps Louisiana, with a suitably ambiguous border in the east as what characterized Acadia. Or they trade it or parts of it to obtain French Canada back and or Acadia.
If France exchanges Louisiana or even just the Eastern portion of it...the pressure on Br. America is removed to a more acceptable distance, but they can still project influence to the traditional native allies.
There probably won't be an offer to exchange any of the islands in the Caribbean for French Canada, as the British will probably hold less of them, just how many depends on when and if French Canada is captured...there is definitely though enough divergence to delay the capture of Havana, allowing for greater reinforcement and fortification making a more difficult
siege, that may fail or simply out last the war.
oooohh...lets see potential for instance for French Canada, Revolutionary America, Br. Louisiana ( the later two under the right circumstances of course, and Spanish Florida.