Pressure has nothing to do with pipes freezing. It is just exposure to cold.
yes
It is important to protect water pipes so they don't freeze because when water freezes, it swells. If water is trapped inside the pipes the pressure from it swelling will cause the pipes to burst.
Gauges also have a water connection, so it's possible that it could be frozen as well. Alternatively, your gauge could have failed from frozen water causing an overpressure condition on the membrane that it uses to measure pressure inside it. You probably will need to have it replaced.
If pipes are frozen no water can flow, so water meter shouldn't be registering anything. But if pipes are frozen it's a good idea to turn the water off at the inlet. That way you have a chance to discover and leaks and damages when the pipes thaw w/o getting the whole place flooded.
Broken water main. Water plant pump failure. Frozen pipes.
Usually you should if your pipes are at risk of freezing. (i.e. you live in a cooler climate and the house has no heat.) The reason for this is that even though your pipes are drained, there is still water in the low spots, which when frozen will expand causing pressure build up. If the air has no where to go it could cause a crack and probably some water damage when ever you do turn on the water. }th0rn{
Singing water pipes can be caused by air that is trapped in the pipes. The air can cause a whistling or singing sound, or it can cause the pipes to knock or rattle.
No That is usaully do to an over pressure of the water system
If there is no water, or there is low pressure, then there are a few things that can be done. Search for incidents in the area, and try your cold kitchen tap. Check your stop valves, as well as check for frozen pipes.
water expands when frozen.
They shake because, the water exerts pressure when running in the pipes
Salt water cause corrosion on most metal pipes.