Hmm, I'd say about 10 Minutes. But 15 just to be safe.

Same as Aaron. I'd just add that they should do the regular team warm ups, then break off and do pitcher specific warm ups for another 5 before working with the catcher.

It just all depends on how long it takes her to loosen her arm. When she is warming up she should start feeling more and more loose and when she does thats when she stops.

10-20mins would be fine and it also depends on the weather. It also depends on how your pitcher feels, if she needs more then she can go longer. wearing a jacket may help if weather is colder than usual

http://www.softballperformance.com/softball-pitching/frequently-asked-pitching-questions.html

it really just depends on the pitcher. i personally take about 10-15 mins. if it is really cold out it takes longer but on a normal summer/spring day its 10-15 mins.