Russia is a nation unto itself. It used to be the U.SSR which encompassed countries like the Ukraine, Chezolavakia, East Germany and several more. Now it let them go and each is a separate country.

Not in the nearest future. 80% of the population are ethnic Russians with absolutely the same culture - the difference is less than e.g. between the US regions, and the parts of the country are well integrated economically. So there are no natural reasons for fracturing of the country.

I hope so, after Putin will gone, there will be power vacuum. Sibir region already proposed referendum about future autonomy. Same in Kaliningrad, they are realising now, that they are closer to Europe, than Moscow

There are some countries that were once part of the USSR but are now independent.

Only after EU, China and the U.S. Especially the U.S. 50 independent states. No less.

doubt it

history shows, it is only expands