Extreme cold for me is 5°F so I won't opine on clothes for colder than that. But I will say something about the bike.

Based on my one ride during a serious cold storm, riding through ice and snow where it was wet enough that ice built up on the bike and goggles and other parts, I have no inclination to do that again with a geared road bike. When you're stopped in less than two miles, chipping ice to get the chain moving, it's kind of late to be thinking about better choices.

Next time it will be a single speed with big tires, preferably studded, or else I'm staying home.