AHC: A Canadian Manifest Destiny.

Similar to the us concept of Manifest Destiny which practically made them expand from coast to coast, and also to promote filibusters, how exactly could you get the Canadians, or british North America to expand in a Manifest Destiny like way, including territories like Alaska, Oregon and maybe even california?

Obviously more immigration would be a boon to such an ideal, but it would depend on how much territory they could grab, right?

As you say, more immigration would help. Also I'd say that, if say the USA, after the Revolution, managed to take some, or most, of of the British Caribbean, then we could see more Loyalists pouring into Canada - either from the Caribbean itself, or those who IOTL went to the Caribbean from the mainland.

Very unlikely. You would need to depopulated all of Ireland then cram them at the Mouth of the Colorado River to cut off the Mexicans and Americans from reaching the areas first.

Actually if you look at population growth rates from 1790 Canada has grown faster than the US:

Canada

191,311 to 33,476,688 (2011) population has multiplied by 174.986

US

3,929,214 to 315,085,000 (2012) population has multiplied by 80.19

So you can see Canada has grown twice as fast as the US.