I don't know if this has been discussed elsewhere, but this sentence reminds me of Sweden's tradition of watching an old Disney cartoon every Christmas Eve. It's bizarre to outsiders, but very serious to Swedes.
It's not actually ALWAYS the same things--they have gradually switched out some of the shorts and tried to edit out the more racist bits. And, they reserve some space to put in clips of their up-and-coming movies. Some free advertising for Disney...
And, this bit from the Wikipedia article: "In the 1970s, when SVT's head of children's programming disclosed plans to discontinue the special due to growing anti-commercial sentiment in the country, public outcry resulted in the special being maintained."
Now I finally understand! Recently I was hiking in Sweden around Christmas time, and I slept in unmanned huts (stugar). One of these huts had a guestbook in which a previous visitor had left a message: he had stayed in the hut on Christmas and missed Kalle Anka. I didn't get what Donald Duck had to do with it, but apparently it is quite a thing to miss at Christmas ;-).
hans vänner is part of the subject here, so there's no need for reflexive pronouns yet. It may be a bit easier to see if you consider that without Donald, the phrase would have been Hans vänner önskar..., without sina. So the och is just glue for the two parts of the subject.
No, that's not correct. We use simma if you're doing some kind of actual swimming that moves you - like breaststroke or backstroke. Obviously, you can't do that in a bathtub, but the distinction has nothing to do with where you are. To bada i sjön is perfectly idiomatic Swedish, for instance.
American English is more likely to make that distinction than British English. British English uses it more as devalanteriel says in his answer. You can go bathing in the ocean, or a lake, without actually swimming. And bathing doesn't necessarily imply cleaning yourself with soap....and nor does "bada".