My experiences with CDG have been many and varied. Most of the time DL coded flights on DL or other metal are bused to outlaying regions. Most DL coded AF flights have left from the main termnal. But the operative phrase here is most of the time. YMMV

As for the cold, I've noticed the flights boarded from the upper level have pleasant temps in the waiting area. The lower level can either be freezing or stiffling. Or neither.

I never know what to expect at CDG so my motto has been plan for the worst and hope for the best. Airport management here marches to a drummer that only they and Satan can hear. Take the coat.