As is documented by my too many too long comments, which I now deleted, I find the current form of the question too unfocused/imprecise to be reasonable. In particular, it does what is in my opinion a main error for an MO question, namely it tries to combine (at least) two questions.

However, a big-list question along the lines of one of the implicty questions:

"What are things to keep in mind when applying for a PostDoc for various countries. Please specifiy what 'PostDoc' means precisely in that context, or what differen variants of PostDoc-like positions there are, and list information that seems relevant to that particular country / academic system. "

This is something that could work and be interesting. In particular, as PostDoc can mean various things in various systems. And is also not too subjective.

The other implict question: "How to apply/Should one apply for a PostDoc at a place where one knows nobody?" I am a bit less convinced of the usefulnes of this one. As I doubt there is much to say, except try to find and stress a link and/or contact somebody there or something like this.

In any case I think one could wait a bit for clarification.
In other words. I do not yet vote to close.