Finding stuff for roofing in the winter sucks. My boss swears by blacklader pants, they even have kneepad inserts. Wear layers under your pants. Long John’s and or fleece pants will keep you warm. Gloves are also super hard to find, or hard to find ones cheap (and warm) enough you don’t mind destroying.

I follow all of your rules, but let cotton be my top layer sometimes, as it is fairly cut resistant (we do standing seam). As for boots, muck boots seem to be warm enough and give you good traction on a panel/ underlayment.

I also bring hand warmers in case my hands start to get too cold. Also some people use the Milwaukee sweatshirt that is heated/battery powered as a mid layer. It may reduce too many bulky layers.