Yes, the pitcher has to be in contact with the rubber or if not the pitch will be illegal
Any pitch from the pitcher that can not be caught by the catcher with reasonable effort.
The speed varies from pitcher to pitcher but the average is about 85-100 depending on the type of pitch thrown.
In fast pitch, a runner can attempt to steal as soon as the ball has left the pitcher's hand.
The King and his Court.
43 feet in fast pitch
College softball pitchers, pitch anywhere from 50mph to about 70mph. But 70mph is about the fastest.
When the ball is in the hand of the pitcher inside the circle , baserunners may not advance.