What are the operating temperatures for the infared motion detectors? Specifically, will they function as expected in [-40C/-40F] cold?
A lot of people don't think they work at all. So yes, in that sense they will continue to function
as expected in -40C/F cold.
Are they weather resistant?
Sure... as long as you keep them inside when rain or snow is forecast.
How about the night vision and other cameras? Do they work properly in extreme cold?
Same answer as for the motion detectors.
I know the motion detectors are battery powered, how about the camera(s)? Are there AC and DC models offered?
They all use a wall-wart-type 9 or 12 VDC power supply, but there is a battery pack available for some models.
Do the pan and tilt mounts sieze up in cold weather?
I wouldn't have much confidence in them not self-destructing at -40C/F
(Please excuse the levity, It's been a long, long day.)