True, although would the Brits want to create a hyper-Canada in the first place? It seems more likely that they'd have two dominions, Canada and Louisiana.
Unless there's an alt-1812 with Britain getting some portion of the Northwest that's the most likely scenario. And even in that scenario it could still happen.
A lot depends on how the confederation talks happen, having more (and stronger) British colonies really changes the dynamic from how it happened historically. And it would be so far from the POD that anything is possible. My guess is that a union of British colonies has a lot more benefits that drawbacks and that Louisiana would end up joining whenever it occurs (1850s imho). There would be a lot of nuts and bolts things that benefit it.
But the hyper - Canada is so far down the line that it skips a lot of the interesting debate about other things.
1) Britain and Spain, especially regarding Texas and Florida. Britain had been mucking about is Florida since the end of the Revolution and Texas is ripe for a takeover and in the midst of a rebellion.
2) America. Is there a war? They went to war historically, but now there's a much more important prize... New Orleans
3) American finances. Without New Orleans and the western territories the federal government has just lost a massive source of revenue, what does it do to make up for it? The government (and citizens) were virulently anti-tax.
4) Britain, Louisiana and slavery. Does it get phased out with the rest of the empire? The power of the planters will be even more of an issue if Britain gains Texas too, then you have a sizable block that has a vested interest in the institution.
Debating hyper - Canada is waaaay past the POD, there's too many other issues that need to get solved first.