Really? Did Russia lose or gain land?
As far as I know, Russia did loose dozen of square kilometers, irreleveant to overall scale. It was about "direct-line" border, which is unconvinient, which was replaced by "border along river". Plus some patches to "equal balance".

You mix up different things. Uprising is not subject of nuclear war at all. Regular army will supress something like Chechnia (and so it was). Talking about "Siberia uprising" is something like talking about "Kansas uprising". Not in this reality. In any case it is about INNER conflict.
China army inside Russia borders completely differs.