[quote=@Iluvatar]
Am I allowed to be the highly autonomous Grand Duchy of Finland in the Russian Empire? It might make the eastern front a bit more interesting, and would make a nice point of conflict between Germany and what remains of Russia after the German invasion (and presumably revolution).
[/quote]

Yes, you can.
Though as I told Dinh, I'd advise you to work out something with the person who's playing Russia on how you want the whole "Autonomous" thing to work.