Regarding that last bit, on the ump's judgment being final, unless I misunderstand, it can be reversed, as I seem to recall in last year's ALCS that the Red Sox had a home run that initially wasn't ruled right but after the crew met up they reversed the call.
At least, I think that's how it went...
Depends on the situation, and not when a pitch is called a strike.
Only if there is a umpires decision that is in conflict with the rules.