Kind of echoing @Noneshallpass here, but I think you can make the ships work in different ways. As he pointed out, a lot of people will paint the tips different colors to differentiate, or you could use different color chips. I’m more like you two though and like a unique sculpt.
I think you can find most of these on their site. Look at the 3D printed units section too. Some nations have battlecruisers there. True, you’d need to paint them, but their there.
You could also get a little creative. Use the neutral nation cruiser as a “light cruiser” if needed, and use the A&A OOB cruisers as your Heavy Cruisers. Maybe use the OOB battleships as your battlecruisers, and buy the HBG battleship types for your fast and regular battleships? Just thinking out loud.
I’m with you of course on South America. But as @Noneshallpass said, it’s based in history, and there wasn’t much happening there. I will say though that the Latin America expansion is the way to go to get them in. I plan to use that every game for the very reasons you mention, I want to get that part of the world in the game!
As for the USSR, I kind of get what you’re saying. But at the same time, there’s a lot for them to do. The Chinese and Spanish Civil wars will certainly be fun to play. And you of course will need to be prepared as the USSR. Border clashes with the Japanese are in play too.
Don’t forget that the USSR can attack minor nations starting July 1939. So while that won’t bring their income up, it’s still something to do if the Axis have left them alone.
The maximum time the USSR might spend at 8 IPP is 6 turns. So, it’s not too crazy I suppose, especially since those early turns will go a bit quicker with less combat movement and battles to play out. But if the Axis are going out of their way to make sure the USSR doesn’t increase at all until July 1939, I’d be surprised to hear that is fully a good thing for the Axis!
I think there’s enough side stuff happening to keep the Comintern player involved, but maybe that’s just me!