Well, you write a sentence on email? Ths is the ask part.
Expect to be ignored. It may be illegal (like germany) or complex. Take the euro to your bank, send them to a broker (except what you need), buy bitcoin.
1: Possibly, possibly not (i.e. Germany: No.
2: Your problem. You get Euro X, this would result in the employer taking off taxes and then buying from taht Euro X bitcoin, which he sends you. Fluctuations are not his problem.
3: Depends on country. In germany not at all.
4: Not at all? Iti s one of those battles not worth fighting. As employer, particularly one in a non crypto field, I would rather replace you than put that trouble into my accounting side (and I say that are someone invested very heavily in bitcoin). PLease take my local currency and do with it waht you want, but do not bother my backoffice with it.
5: Yes. It is.