Some criticisms:
1. I believe far more of Latin America will offer token support to the United States. For example, Brazil sending a few thousand soldiers to fight would help to reassure the U.S. about its expanding presence in the South Atlantic, and cost very little in their eyes. Columbia will of course side with the U.S. It's geopolitical imperative is to ally with whatever power controls the Panama Canal, and Argentina will ally with the U.S. as it will have been a tacit U.S. ally since the 2030s. It will send a few troops as metaphorical "payment" for free trade agreements and technical and military support which the u.s. will have been giving it for more than a decade as a way of constraining Brazil.
2. Why do you expect Italy to split into two? I don't see that happening: regionalism is strong there, but their unemployment rate is still only at 12%. A general rule for calculating the political effect unemployment has on a country is the "rule of three." That means for every unemployed person three people are affected (generally, a spouse and two kids). That means that 50% of Italy is affected by its unemployment. That's high, but not as extreme as Greece or Spain's. The capital inflows of the Po River valley would likely be funneled South through social welfare programs to keep the country together, and I would expect Italy to give basing support to the U.S. and potentially Poland, but not engage in war b/c it won't want to fight a major war, and Turkey will grudgingly not attack it because it won't want to face Italian power (which won't be great, but will be regionally relevant like England's, despite its population decline problem which is even more extreme than Germany's), in addition to the Polish Bloc.
3. I expect the Indonesian central government will be allied with the U.S. while Japan destabilizes the country by pitting ethnic factions on different islands against Jakarta. It will be neutral in the war, internally distracted, but will be rooting for a U.S. victory. Southeast Asia will also want to see a U.S. victory, but stay neutral until its clear the Americans will win because they will fear Japanese power projection in Asia. Japan won't need to invade them as they did in World War Two because they will have the resources of Russian Siberia.
4. Any and all Canadian states will ally with the U.S. None will want the U.S. to favor one faction over another after the war. I don't think Canada will split, but if it did, all those states would have to be pro-American as they would all be hugely dependent on the U.S. economically, and militarily fearful of the U.S. supporting other Canadian factions.
, but overall, very very well done.