A/C recharge

Everything will work, but the purpose of pumping the system into a vacuum is water will boil and vaporize at 77 degrees Fahrenheit in a perfect vacuum. That makes it possible to be drawn out. If it is too cold for the water to vaporize, some may remain in the system. It combines with refrigerant to form an acid that attacks metal parts. Also, if there is too much water in the system, it can overload the receiver/drier, then if any circulates, it will freeze at the expansion valve and stop the flow of refrigerant until it melts. That can take as much as an hour, then the system will cool again until the next time that droplet makes its way around back to the valve. If possible, I would want to get the vehicle in a warm garage for a few hours, then evacuate the system for at least a half hour.

Probably not. What I would do, if you have a charging station, is to put in a few ounces of refrigerant to keep it under a little pressure. That way, with changes in barometric pressure, the system will not go into a vacuum. Seals should not be a concern, but if the compressor were to use a rubber lip seal, those are good at holding in pressure but not vacuum. The goal of having a little refrigerant in the system is to prevent the possibility of air being drawn in, along with the humidity in it, past a lip seal or any other small leak.

Even if some air was to be drawn in, the amount of humidity would be rather low in cold weather. It is more important to pump the system into a good vacuum just before you are ready to pump in the refrigerant. Also, even if you leave it empty, it must be sealed to prevent air from circulating through the system. People do the most damage when they remove the compressor, (or some other part), then drive the vehicle like that for days or weeks before installing the replacement part. Dust and road dirt can find its way in too which can block the expansion valve or orifice tube.