I'm in Copenhagen - and I love it! Would find it hard to move back to UK now to be honest (been here 8 years).
- Regarding your queries: yes housing is expensive but you could get a very nice apartment in an expensive part of CPH for your budget, or a house with garden further away (but still well within commuting time
- Car - I wouldn't bother, I haven't had one the entire time I've lived here + I have 2 small DCs who bike to nursery/school. If you live in CPH it's completely unnecessary. We are members of a car share (letsgo.dk) which is pretty convenient for those moments you really need to drive somewhere. But do bear that in mind when choosing where you want to live
- Jobs: We moved with DH's job but I got one fairly quickly - it sounds like your DH is in research, in which case the language isn't really a problem at all. The science community here is very international.
4: Language: The kommune usually offers cheap language classes to EU citizens and as long as you make at least a minimal effort to say a few words, most people are happy to speak english. That is a little different outside Copenhagen though.
5: There is an active and very friendly expat community here. Expect a bit of culture shock and the usual expat whinging (I'm sorry to say), but once you get used to the Danish way of doing things, you will find it hard to live elsewhere. It's an amazingly efficient country and the people are genuinely lovely. The reputation for standoffishness is I think simply a different style, that is often misinterpreted.
- Taxes. Yes you're going to pay a lot. But you get a hell of a lot back in return. The quality of life is very high and it is very easy to live here as a family, I have not bothered putting my kids in the (uber expensive) international school. The danish education system is excellent and as they were born here they have no problem with language. That would be somethign that you may have to weigh up though depending on how long you think you'll be here. Be warned though. We came for 3 years and now own a house here!
Hope this helps!
Good luck...