No, you're not owed anything.
Winter happens in Canada, routinely. When making a very long haul flight, the plane left the gate maxed out on fuel (not necessarily full to capacity, but very likely full to takeoff weight limit). So it's not as if they could simply have loaded more.
And 4.5 hours on the ground burns TONS (literally) of fuel.
Further, YOU CHOSE to pay the upgrade to first (which, I concede, is a ripoff) on the connecting carrier the next day.
DID YOU CALL your travel agent in Canada? You should have- they could have worked something out. But you haven't mentioned that you did.
The predicament of a long ground delay due to wintry weather is not AC
's fault, so you're owed nothing there.
And the expense of the connection upgrade was something you took on voluntarily, so you're owed nothing there.
But, as was said above, if it was all on one ticket, then you might get something for the misconnect. But probably not, as it was due to weather. Full flights aren't anybody's fault, either, so don't expect them to have much patience to your whine about having to upgrade.