Just right-click -> create measure... make sure your measure type is Exceptions > Count. All other fields should be pre-populated based on your selection (but just double-check all the info is correct) then click OK.
You now have a measure that tracks the occurrences of this exception, and you can use it within charts.
Correct. You'd have to create measures for each exception you want to chart over time.
As far as I know there are no other quick options for the kind of breakdown you require.