Well, Scandinavia ain't tropic by any means, so house fires started by lightning is rare. However, if and when they do it's on farms, barns of wood, that catch fire, not really any cabin or house were inhabitants are human. Barns are made of wood entirely and often contains hay. Go figure. Real houses have concrete (mostly) reinforcing iron bars, lightning rods on the roof, and that faraday cage built in, like car, anyway. If a house is struck, the fire that may evolve limits itself to small spaces and very rarely catches on. There a a few old houses with "hay roof" on them, that are more vulnerable, but as it mostly rains a lot at the same time the lightning strikes it is put out anyway, on the outside. I've yet to hear of or read of any instruments or other valuables lost in lightning house fires in Sweden. Maybe on the 60's or 50's where it wasn't really up to snuff yet. However, OTHER fires occurs, at christmas times, candles left on and yada yada...too hot heaters and whatnot. I would even go out and tell that when it's really cold they heat up the heaters too much, and THAT in turn makes fires that can be more devastating.
The most thing to make sure of is the power grid, and power lines in the house, moreso than the actual construction of the house. You can build them to
just fry the electrical equipment, but the heat generated from around it should not catch on, and stay and start other things to flame up. It's the remaining heat from the wires after the shock that catches on, and that is the worst culprit. It's the plastic that's melting that's the evil thing, I wish the old and heavy bakelite came back...
Still, I am feeling sympathies, and grief with you. It's not encouraging to watch those pics, at all. While me myself have a few "desert island" items I will grab before the fire things strikes, it's mostly photos, negatives, and so on. Wouldn't be interested in collecting art, just for that sake. If it goes up in flames, very few insurance companies will pay for it. If any at all. I tried looking for a special insurance of my Klein electric, but no one wanted it. If something happnes to it (stolen, lost, fire, whatever) they just pay the nominal price, after they do a reduction of the value of what it cost when bought new.
I hope you can at least claim some of it on insurance. I know you can't replace that but it'll at least help. Also starting a go fund me page is a good idea as well! I'm sure lots of people will help out, especially after seeing those pictures 
