This is a great thread!
Back when I lived in Alaska and had a full household, I found that wool just worked better than anything else overall. My kids and I were all pretty hard on clothes and I found that wool did the job well and survived to get passed on to the next kid, while a lot of synthetics didn't. When I needed outdoor gear, I went to a military surplus joint. Some of these surplus shops are really upscale. You don't want that kind of store. You want the place that looks kind of like a garage/ rummage sale. The international military (much of what I bought was german or russian military cast off) has lots of pretty good quality wool clothing and I could get it for near thrift shop prices.
Wool protects even when wet, wears well, and has the great benefit of not turning into shrink wrap when it gets hit by a spark (like synthetics do).
For feet, the gold standard is bunny boots. the newer style is rubber, but the old style (which I used to wear comfortably at -50 to -60 degrees fahrenheit) had a hard felt outside (the bottoms were leather and way too slick on ice). Snow mobile boots with felt liners are what most people could afford. Get an extra pair or to of liners, so you don't end up with wet feet. Get them a little roomy (not sloppy) so you can wear an extra pari of heavy socks. If you can get them or make them, mukluks are wonderful.
The old time athabaskans in central Alaska often wore a big set of heavily insulated thumbless outer mittens on a cord around their neck adjusted to where their hands would be normally. When their hands weren't in use, they kept them (maybe with secondary gloves) in these big mittens. When they needed to use their hands, they pulled them out, did their work, and put them back into the big outer mittens. This is a great idea, in many situations.
For stopping the wind, I have nothing against leather, but it can be pretty heavy. Another alternative, especially for the vegan crowd, might be oil cloth. Here are a couple of links for how to. https://www.youtube.com/watch?v=iqjfwhirsVo
or waxed cloth, this example is 90% beeswax and 10% parafin https://www.youtube.com/watch?v=-6G8MG8Qfhg
Note: I haven't made oilcloth, but I understand it can take up to a few months to get to the point it isn't sticky, so best to prepare it in the summer, let the sun hit it to help the oil polymerize.
A good hood is better than a hat or scarf.
Looking at old history. I've often felt that the old medieval hood that covered your head and shoulders but was not part of the coat was a great idea. Also, everyone in the world used cloaks, which is basically just a blanket with hooks to let it hold around your neck, part can be brought forward to form a hood. They didn't do this because it didn't work. In our current time frame though, for a man (particularly) to wear a cloak is a visual announcement "Hi! I'm either an overdramatic theater major or I'm a bit bonkers". This is unfortunate, because in some settings it is a very practical piece of gear.