Yugoslavia is bound to explode, the only thing that can stop that is preventing discord behind the Iron Curtain. The Soviet Union needs to be more successful, have less uprisings in Europe, and no signs of faltering.
Anything that keeps both alive and healthy is going to involve some events back near the end of World War II, into the 1950's, particularly involving Stalin's successor. However, you can still have a unified Soviet Union even with the events of the 80's, but Yugoslavia isn't going to stick around.
As for a "democratic government", no to either. Anything that succeeds the Soviet Union or Yugoslavia will not be democratic in the liberal sense for years to come.
Edit: I don't I really answered the question right, but I think the answer is simple for Russia: "elect" a more transitional president. Yeltsin's economic policies raped Russia, admittedly my knowledge of the candidates isn't large outside of Zyuganov or Yeltsin, but even Zyuganov would ease the stress on a newly born Russia.