I doubt the camera itself stopped working in cold weather. Anything's possible but I think it's most likely that your cars had some frost on the windshield right over the lens. It might not take all that much frost to diffuse the image enough for the camera to fault out.
As far as snow clogging the radar antenna, yep, happened to me in slushy snow.
I mostly don't care about these issues since I rely on my eye to see road signs, I never use LKAS, and I positively despise CMBS and am looking for a way to code it off permanently. A blocked radar will disable ACC, so when mine got covered in snow and slush I just changed the cruise mode from ACC to good ol regular dumb cruise control and kept on trucking till the snow fell off the antenna and the fault message cleared.
It's concerning how much people are getting used to relying too much on the car. I read on another forum that someone reported that LKAS malfunctioned and tried to steer him out of the lane and this person's first response was to wrestle with the system rather than pushing the MAIN button and shutting off LKAS. Maybe, as an instrument rated private pilot, I think about these driving aids differently. My flight training tells me that the immediate reaction to any autopilot abnormality is to hit the A/P disconnect button and to hand fly the plane; NOT to wrestle it for control.
It's also likely not a coincidence that the MAIN button in our cars is in the same location relative to our RH thumbs as the autopilot disconnect button in every modern general aviation and transport category aircraft.