For starters, they would need their current government to agree with that plan.

Or they would have to declare independence while their government is actively engaging in genocidal policies against them.
In that case, this fact needs to be widely recognized. They might even receive international help for their struggle.

Another option is declaring independence when the previous country is already falling apart.

In any case, for a successful declaration of independence, the group seeking independence would need to be a distinct ethnic, religious, or linguistic community that lives in a specific region and is a majority in that region.

Were there any precedents in US history when a president lost after one term in office and then tried to run again in four years?

I think the pact itself was no more than a formality. The Russians de facto controlled all those countries so they decided to write that fact down somehow. Some kind of a cargo cult mimicking NATO, I'd say.

I often come across sentences like 'Caesar led his men into winter quarters' or 'Hannibal spent the winter somewhere before attacking the Romans.' This raises two questions:

1. Was it possible to wage winter warfare in regions with milder climates such as Palestine, Carthage, or Sicily?

2. When did European armies stop winter quartering and start winter fighting?

Were there many examples in history when a Shia dynasty ruled a country with a Sunni majority (or vice versa)? If so, were there any revolts on a religious basis?

They also Germanized a lot of Slavic (and Baltic) lands in the Middle Ages, including the land around Berlin, Silesia, Eastern Prussia, etc.

Why are you so surprised? Stuff like that kept happening after that, too - in Asia, Africa, and Europe.

The USSR, for example, was far more conservative, had a pact with Germany, and even seemed quite sympathetic towards the Axis powers in 1939-1941. However, it is hard to imagine that its alliance with Germany would have lasted forever. In the 19th century, European countries did not have many ideological differences, yet they were constantly at war with each other.

It was extremely popular in the Soviet Union (for obvious reasons), and the developing world was under constant influence from it.

No, dictators should not be praised for overthrowing their rivals.

Was the Chinese currency named after the Yuan dynasty?