i agree with andydi. when i get up now in the morning in the winter in chicago, i just put something on my torso. (ok, i wear something on my feet all the time (crocs mostly) but that's not because i'm cold, just because i need to have something on my feet.) anyway, my long sleeve shirt/sweatshirt keeps my pretty warm until the weather gets seriously wintery. then i'll put on pajama pants as well, all until i shower and get dressed for work.
Robe. A cotton one for when it is cool, a heavier flannel for when it is colder, and a really thick one when it is quite cold. But still free and easy underneath.
I find robes to be more burdensome than regular clothing, despite being open below.
Rarely. My wife is cold blooded and she cranks the heat during what little winter we have...
So does mine. But unlike you, my lower midsection is cold if anything is so I am more likely to wear shorts than a shirt.
It is not uncommon in the evening for me to be wearing nothing or shorts and she is in flannel PJ's and a heavy robe!
In bed it is always nothing for me and she still need the flannel PJ's in winter.