Eire, no such event ever took place during the ACW. Some silliness in NYC thought they could trade with the south and were disabused of that notion.
Faeelin, to the point of making demands they know they'll never get, leaving them with egg on their face?
Well it would need to be a great big PoD, but it's hardly impossible.
No War of 1812 would probably lead Canada to joining the USA eventually.
How do you figure?
It's also worth keeping in mind that if the hypothetical Anglo-American war was a limited conflict between just the two main powers, America might not have launched a full-blown invasion of its' giant neighbour. There might have been raids and attacks, possibly even occupations of some territory, but for anyone to invade a country the size of modern Canada would have to be part of a World War-level conflict.
It definitely wouldn't be in one massive invasion, but a series of assaults at strategic targets and population centers. I'm thinking a land corridor through to Alaska (Big chunks of BC and Yukon), the GTA, Regina, Winnipeg, Ottawa, to begin with. Maybe offer Quebec independence. Then the next wave at natural resource deposits. Then the slow assimilation of the rest (possibly in "autonomous zones" in the interim), but there isn't much of a military risk once the major population zones were occupied/pacified.
What if Russia showed a little more intrest in North America early on, but then looses interest: Instead of taking Alaska and a few coastal forts/trading outpoasts further south (like Fort Ross near San Francisco) they get Alaska and OTL Yukon, BC and part of Washington... Then the Alaska purchase includes all of that territory as well...
Since Canada is an independent nation Great Britain has no authority to sell Canada in the first place, Canada will not agree to being purchased and has more trained soldiers than the US does without the 1917 mobilization, and the idea of the US telling Canada to surrender or we'll let Germany seize territory in North America is beyond implausible.