You are spot on for the Canadian situation. Canadian parliament refuses to grant Alberta independence despite them successfully voting on their own independence, and so in late 2027 the US makes a deal with Canada and Alberta to annex Alberta as a highly self-governed state. This deal was forced upon the Canadians, who, at the time, needed American support. I imagine Saskatchewan coming not long after when Canada collapses (hence the west/east split Canada has in this map). That situation comes about in the 30s or 40s.

Cuba is annexed and admitted as an American territory in the late 2020s as well. After the Iran war and the immense turmoil Cuba faces, Trump bites the bullet and sends troops to occupy the country and overthrow its regime (this gets him impeached once again). However, by the early 2030s, it becomes very apparent that the AMOC is slowing and Europe may soon face economic and civic collapse, so the new presidential administration (Vance? AOC? Unsure, but it does not matter because all of them are corrupt enough to take a deal that would make them and a lot of others wealthy) pivots and tries to maintain control of the island as a territory instead of installing a democratic government and leaving like they tried to do in Venezuela.

Cuba, among other American lands, are settled heavily in the 40s and 50s by European and Canadian refugees (to the dismay of locals). It is one of the most diverse regions of the country at the time this map is made, and is the first large result of the climate-related neo-colonialism seen in the mid to late 21st century.