Pokój is also Slavic. In Russian related word means something closer to "calmness" and sometimes has overlapping meaning with English "peace". Like "peace" in "peace and quite" for example will be translated with "pokoj", while "mir" in the sense of "peace" means only the opposite of "war".

I assume colors show the original meaning of the word, not the language family.

Edit: whoops, missed your first first question. Yes, fred et al come from Proto-Germanic frithuz, which is constructed from frijaz (free) plus noun suffix -thus.

Well as for the first second one, language families tend to have different roots for the same thing, of which different ones will become preferred in different regions. Both of these words actually work in both Russian and Polish, it is just that one of them is archaic.

As for the second third one, I don't think they're supposed to be the same colour. As far as I know, they are unrelated.

For your third fourth question, no clue. I might look into it someday.

Old Polish does have a "mir" with a sense of "peace", but also a sense of "respect / ad-mir-ation".

The word itself comes from: Reconstruction:Proto-Slavic/mirъ

...with nice things like Old Persian 𐎷𐎰𐎼, and less nice modern things like the case of Mitrofan the bear.