Pretty much every commercial pilot is ILS rated... but it depends on the airline if they are okay with landing in fog or with extra expense flying all the way back and providing a hotel;)

I'd expect a Scandinavian airline to be prepared for bad weather; rain, fog, and snow are completely common occurrences in all major Nordic airports, can't see why nor how SAS would be able to operate without pilots being well-trained on flying in bad conditions.

How many "major nordic airports" are one tiny strip of runway next to a bunch of steep terrain?

You lost me, I don't know what you are trying to infer, can you be clearer?

Can't help ya. A big flat major airport in fog is different to a tiny runway with steep terrain in proximity in fog that's just it. If lose ILS at the wrong time, some turbulence and you meet a mountain.