Yeah, Switzerland, or the friend I mentioned who grew up in Luxembourg - that country is kind of unique at least in the West in the way its division between languages is based more on different domains of life than on linguistic groups. Luxembourgian children are taught in Luxembourgian, French and German at different stages of their education, and people generally use all three of those languages in their daily lives. Throw in the inevitable English, and I guess that makes four without too much effort.

Not sure Finland is such a great example - you could suppose that they're all trilingual Finnish-Swedish-English, but in my very limited experiences, not that many Finns are genuinely fluent in all three, even if they all have some knowledge of the three.

It does come back, fortunately, relearning something is so much easier than learning it the first time.

No doubt. My company does some trade with Russia (plus Ukraine and Kazakhstan), and that's all done in Russian, they're apparently not too willing (or able) to do very much in English.