I've been known to be out when it's cold and have developed my own choices. I avoid bulk and stay active.
Feet > A pair of either Simms knee high liner socks (discontinued now) or the Mid Weight socks. Knee high to avoid circulation problems caused by a sock that will constrict just above the ankle. I do not wear multiple layers of socks. That just causes my boots to be too tight which leads to colder feet, air space and ability to have some wiggle room is important.
Legs > I use the heavyweight Carrhart long john bottoms. These for fishing and traveling back & forth to the cabin (150 mile snowmachine trip in cold) Again no multiple layering on the legs under my waders, G4 waders and the Carrhart bottoms and I can stand -8 on a river if I'm in a stubborn mood.
Torso > I like Paragon Merino Wool as the base layer, it's thin and wicks very well. Over that a Simms Guide Top Mid weight, over that the Simms Fall Run Vest. The vest is thin but extremely effective. In combination all three layers work very well and I do not get colld, I wear either a G3 or G4 jacket over the layers and fish on in comfort.
Head > This depends on how cold is it really. I have one of the Gore Tex foul weather caps with the ear flaps that attach under the chin with Velcro and that is usually enough for colld but when it is super cold I wear a fur hat made for me by a lady when I was out at Tuntutuliak but you won't be there I'm guessing................ Any good head wear should do.
Hands > I have various gloves for driving a boat in the cold but when fishing I use old school finger-less wool. A pair of chemical warmers in the palm and backside of each helps when it's sub zero but you still can get frostbite on fingertips...........
I'm not saying that what I use is the best or that it is colder here than other places but those combinations allow freedom of movement and I stay comfortable enough considering what I'm doing
One thing for sure, when you find things that work then stock up on them. I have 3 or 4 of everything I listed except the jackets.