For these questions, answer it by using what most good players play with, not just the “actual” rulebook. So use LHTR or what is standard by “expert/tourney” play.
Lets say Moscow fell to Germany, then Berlin fell to Moscow, but Moscow is still owned by Germany.
1)Does Russia still collect Germanys income?
2)If so, is Russia able to buy things with that income in Berlin?
3)Can Japan take over one of Germany’s start-of-the-game-territories, which is currently still owned by Germany, by placing one of Japans units on it?
4)Can Japan take over one of Germany’s start-of-the-game-territories, which is currently owned by the enemy, if it had a land unit survive the battle for it?
I think it’s:
1)Yes
2)No
3)No
4)Yes
You would think that #3 would be yes. Why wouldn’t you be able to use that countries territory as your own, if you entered it with a unit? Its capital has fallen, you would think the populace would work for you, being an allie and all. How is this much different than #4?