you play the whistle; the ref has the last word. You can ask for a time out, and then talk to your ref, but if it's a good ref and they don't call it then it usually doesn't count.
There is no such thing as a foul in volleyball.
when a foul is committed in volleyball that team/side losses that point and gives the other side the serve.
Then there would just be a personal foul and the team that got fouled would keep possession.
Happens when a foul is committed inside the penalty area. (e.g. bad tackle or handball).
If your foot is on the serving line
No. It is encouraged.
If the catcher catches the tip the batter is out. If the catcher does not catch the tip, it counts as a foul ball and the batter continues at bat.
It would depend on who committed the foul. A foul committed by a defender, against an attacker, in the penalty area is a penalty kick for the attackers. A foul committed by an attacker, against a defender, in the penalty area is a direct free kick for the defense.