It's a very interesting concept. I wanted to do something with Vorbeck in my own alternate history timeline (and I might still), but mine deals with the extreme of communism, whereas yours stays more "centrist."
Your original question: Additionally, this story touches on something which I have often wondered–without the presence of Nazi Germany or an otherwise stable and threatening Germany, how would the rest of Europe–especially countries like Italy, Poland, Hungary, or France–developed and interacted?
Italy probably remains fascist. But without Nazi Germany's influence, their racial laws would probably not have been enacted. So Enrico Fermi, who was an Italian who came to America and invented the first nuclear reactor (and stayed in America because of the racial laws), might have remained in Italy and changed the course of the development of the first atomic bomb. The same could be said of the German scientists that fled Nazi Germany.
Poland and Russia would still be bitter enemies. If Hungary goes communist, maybe they would align with Russia and be used as a puppet or jumping-off point to expand Soviet influence west. Inversely, Soviet Russia might feel more threatened by European powers. A war with Poland would probably happen again in the 30s.
France was utterly exhausted after WW1 but had the largest army at the start of hostilities with Nazi Germany. They might align closer with Germany if Soviet Russia exists and is considered the perceived threat in Europe.
Japan would be interesting. If the Strike-South faction wins out, Russia and Japan could potentially align into a shaky alliance if a war breaks out in Europe as well as in the Pacific. If the Strike-North faction wins out, then Russia would be alone. And if Stalin doesn't come to power, the Russian military would be much stronger (no purges).
Hopefully, this gives you some ideas.
