2. The most populous parts of Ukraine are in central and western Ukraine, other than the Donbass of course.1. Presumably
2. Maybe? It would mean sacrificing a large amount of Ukraine and associated economic capacity.
3. The decision had already been made, based on the global shipping situation, in January that there would be no Cross-Channel invasion; the best they could do was Italy and maybe other Med-associated operations.
3. And Western troops on Soviet territory won't work due to Stalin's paranoia, right?