I´m sorry I only read german and not write.
I live in the south of Sweden (skåne) and I can only confirm the other advice. I go barefoot a lot with no problem ( why should it be?)
Sweden is a clean country in general, but because the swedes are hard on beerdrinking and boosing there may be some broken glas.
The places you wanted to visit are going to have 15 to at least20c, for a change the most in the north and there may be some short rain.

Your welcome/ Martin