They're is a few issue with the way you see things:
1) You seem to blend two pretty distinct time periods toguether: the Patriots didn't exist as a party until the late 1810's, possibly, and them being a revolutionary movement with independentist goal is very much an 1830's thing (and even then they where divided on it). By that point France was pursuing a policy of Entente Cordiale with the UK, and therefore never supported the patriots in any meaningfull ways.
2) Related to 1), by the time of the British conquest the whole Saint-Lawrence valley was home to 60 000 settlers, that's it. It did grow somewhat between that and the American Revolution but it never reached anything to what you need to make a bid for independance. It don't quite know where you got the idea that it was that fear who led the brits to keep large forces in North America but its inexact.
3) As Undeadmuffin was saying, the Canadiens and the Colonists tended to hate each other way more then they hated the other metropolitan overlord in the past, engaging into bits of irregular warfare and war by proxi in peace time and being more belicists then their metropolis. To that one must add the fact that the Brits did make pretty conciliant decisions after the conquest, decisions witch the colonists made allot noise against. Now, the revolution did give the newly minted american pretty compeling reasons to forget their historical hatred and led bygone be bygone with the Canadiens but the Canadiens didn't have any so when they had to choose they choose the Brits.
4) France never made an attempt at regaining Nouvelle France because she had come to consider it more trouble then it was worth by that point and was more focused on making conquest in the Caraibean, recovering in India and generally undercuting Great Britain.