They do idle very low when coming to a stop but so long as it dosen't stall your ok, ime the more load, i.e. headlights etc on the more apparent it is.

Yes it will have heated mirrors and they are powered on with the heated FRONT screen, incidentally the washer jets are also heated!

Not sure on the wipers, maybe a loose connection, as the relay is clicking, it would seem the problem lies after this?

Martin