Here's what I figure will happen with the states:
50 States - The 50 OTL American states
2 States - America's Pacific Islands and Puerto Rico and the US Virgin Islands
10 States - Canada's 10 provinces, with Prince Edward Island merged into New Brunswick and the three territories merged into one
32 States - OTL Mexico's 31 states and Federal District
7 States - The Central American nations (Panama, Costa Rica, Nicaragua, Honduras, Guatemala and El Salvador, Belize)
8 States - Caribbean nations (Bahamas, Cuba, Haiti, Dominican Republic, Jamaica, Trinidad and Tobago, the Leeward Islands and the Windward Islands)
This makes 109 States. You may be able to narrow down a few of these, but all the Mexican States are bigger than the smallest of American States and the only Central American nation that's smaller is Belize, which is English speaking and thus much more difficult to merge with any surrounding states, which are all Spanish speaking.
A lot of those states wouldn't exist in the past, and/or were created for political reasons that wouldn't necessarily exist in this timeline.
For instance, Mexico only had 20 states and territories in the 1820s (including Texas, California, and New Mexico), excluding those in central America. Belize was sparsely populated for much of its history, and might get folded into Yucatan or Guatemala, just like how the Mosquito Coast was annexed by Nicaragua OTL. And that's assuming that Belize even exists in the first place, hardly a given assuming a POD in the 1770s. Going back that far, Vermont might wind up as a part of New Hampshire, instead of becoming its own state. New Brunswick and Halifax were part of Nova Scotia prior to the 1790s.
Things get even worse when you bring national politics into it. With Canada and the US territories controlled by a single government, the western borders will likely look different than OTL. Heck, this US, with Canadian states from the start, might not have the great political struggles over the expansion of slavery in the west, meaning radically changed borders there. In a different Civil War (or without one), you don't have a West Virginia.
The 50 state borders of OTL are anything but sacrosanct. Change the politics and you change the states as well. Just a few nudges and one could easily have the OTL continental US having a dozen less states.
And, would one find all of these small islands becoming states? Some might remain territories, others might be forced to consolidate rather than being approved as states in their own right.
I agree on this point, and I'm thinking that Spanish-language education starts entering curriculums on elementary school levels in the United States the 1930s in an attempt to improve the communications skills of Americans, starting in states which will have sizable Spanish-speaking populations. English will have started to have been taught in Spanish-speaking states much earlier, of course, but the reverse will be considerable by the 1930s. (It's also is a way of putting people back to work during the depression.) French would be in the same boat by the end of WWII, particularly in the survivalist instincts that so many French Canadians had remains. As the effects of multiculturalism take hold after WWII, education in Spanish and French expands dramatically, to the point that by the 1970s most American school children get instruction in a second language in elementary and high school, and lots of schools teach them for people who wish to learn for business or cultural reasons, as you point out.
Just pointing this out again, but Spanish wasn't the primary language among the bulk of the Mexican and Central American population in the early 1800s. If there is a "local language" revival in the 20th century, it would likely be more along the lines of Nahuatl or K'iche' than Spanish.