Their heads are the size of a newborns.
if they can't find adequate shelter their ear tips and nose will freeze and develop necrosis
How furry?<br />
My guess is around 35-40 degrees fahrenheit? Just see how comfortable they are by seeing how badly they want to come back inside when they're outside.
Not sure. I had one disappear for a month last winter...was emaciated when we got it back. walking on its elbows...but recovred in a few weeks.
depends on your antifreeze.
something below freezing?