Typically the main bearing goes bad and causes the fluid to leak out. Antifreeze has a lubricant in it which helps to lubricate this bearing. If only water is used in the radiator, this would shorten the life of the bearing. Otherwise, just normal usage would cause it to fail at some time. Premature failure can also be caused by having the drive belt too tight on it. A serpentine belt with automatic tension helps to prevent this problem.
Bad bearing, broken impeller or stuck thermostat most likely.
yes
The use of regular water creates sediments and bad function of the water pump bearing.
yes and no, if the water pump seals are bad antifreeze will leak from the weep hole on the water pump, but it is possible for the pump to go bad and not leak at all.
it get rusted
The alternator is belt driven and so is the water pump but that is where the correlation ends. There is no way a bad alternator could cause a water pump to go bad unless the alternator pulley was warped. Then there is a small chance.
Yes. A pump does not have to leak to break down
the timing belt can cause a water pump to go bad if the belt is on too tight, because that will put stress on the bearings making it wear out rather quickly.
if you are talking about the weep hole in the water pump. that hole will let water out when the seals in the water go bad. that will tell you to get the water pump replaced.
Only if it's going bad. When the bearing and seal are starting to go bad the water pump will leak from the weep hole.
Normal wear on the bearings inside.
When a water pump is bad it will leak. There is a hole in the pump were water will leak out of.
It is rare for a water pump not to work however a water pump going bad will leak coolant and can be noisy from bad bearings.
yes and no. depends on what you mean by "bad" the bearings can go out in it but it will still move water keeping engine cool but making a heck of a racket.