About nose steering - there is normal nose steering, so no problems with that.
Done it many times in VKO and Samedan with apron full of ice and snow and later slush, and steering was way better than my rear wheels drive car...
Only water in the toilet freezes, but that is the law below 0*C
AFAIK 
. That is a standard bizav crew issue to flush it before going to the hotel.
Started up from bateries even at -30c and as high as +40, haven't got any complaints from the engines.
Cannes is doable but outside of AOC, London City not and some other runways below 4000ft. Book numbers are ok for 3discs brakes which were standards after some S/N 1xx (that can be checked) or you can always make an SB and add the 3rd disc each side. First serials were 2discs.
What bothers, regarding the previous question, is luggage space. For 4/5 pax usually it is not enough to fit-in loads of stuff in the back. Internal compartment may help but as long as the crew does not pile up catering/their biggest samsonites-they-could-get in there.
I still haven't seen any reply from Cessna crews
.