Thoughts on the XT-10 (vs XT-1 & 23mm/35mm) in Swedish / European Winter (-28C)?

The first thing you should do when you get out in the cold is to take the lens off for a few seconds. That get rid of the more humid indoor air that is inside the camera. It will in seconds mix with the cold dry air from outside.

The second thing is to leave the cameras and lenses in your camera bag until they reach room temperature. Then you don't get the condense on the outside of the camera.

You can also wrap a blanket, towel, coat or similar around your equipment. That will do the trick.

You also will need extra batteries. They run flat very quickly if it is really cold. If a battery runs flat you can put it close to your body and it will get some juice back after a while.

I live in Sweden and have been using all sorts of digital cameras in temperaures down to minus -35. None of them ever malfunctioned due to it. Even when I often forgot to leave the camera in the bag or had a towel over it. All that happens is that I have to clean a rather wet camera.

The only time you can have some trouble is if you don't follow advise one. If you then have some dust spots on your sensor the humid indoor air will start to condense inside the shutter chamber when the camera get really cold. That means that small droplets builds up around dustparticles and you will get waterrings around the dust spot. That needs a wetcleanig of the sensor to get rid of it.

Don't be afraid to go out and shoot in the cold weather. The camera can stand it outside longer than you can.