I imagine the rule is against people who join and leave to have the people playing one more hero to use.
No, the rule is against any kind of lower number of players using a bigger number of heroes, can be: using a leaver, using and afk player with share control etc, however is allowed to use them for a small time like one boss fight after they become a Phantom player in case of disconnection.
I don't believe we used any of the people who dropped
Yes you used all of them, but the first boss you killed with them was Agiel so I considered this for this time, if this where posting on Black Knight Quest it definitely will be invalid since you already used phantom players for several fights or time, also using Deatch when he becomes afk around 1 hour 58 of game time could cost the replay I considered for this for the low time that he was used and because apparently you didn't know that is against phantom rule.
Overall Excellent Game! +3 Exchange Points.
Quest Status: 2 Reward Pending.