He'd make a roll, count the successes, then roll the failures.
To break the limit, Edge must be used to add exploding dice, rerolling failures does not let you break the limit.
Ah, true. after they commit to not using pre-roll Edge, limits are solid, and the defense test can be rolled first.
Not quite. You can still add dice equal to your Edge rating after rolling.
Correct, push the limit can happen after the roll, easy to forget because I've only had it come up twice so far.
Ok, to keep it solid, have the player state if they plan to use edge prior to roll. if so, have them roll then. Otherwise announce defense result if it exceeds the players accuracy/limit, giving the player the time to decide if he'll then use edge to roll and ignore limits, and thus roll dice, or simply not bother rolling.