Newbie, I think your initial post set the tone by posting ONE issue with mold and then speculating "I wonder if this is going to be an common problem on Teslas in wet weather conditions".
So let's stay focused on this one topic. Please check out the regional forums I listed above. Those do talk about some other cold weather issues and how Tesla is resolving, also best tires for handling in snow, etc. That might be useful for a new owner in Norway.
Bonnie, this you as a moderator implying OP's tone or as a participant?