Advice on the final fight vs the Atropal

My group has started the final fight vs the atropal and I some questions that have come up and I would take any advice that anyone has. My party is going to be casting Silence on the Atropal to counter the wall ability. But that seems like it shouldn't work, and I am unable to find a clear ruling. Also can the Atropal summon a wraith if silenced? They um also opened the door after the hags jumped them and are fighting the hags at the same time. I thought I had timed so that they did the trails and when they went to unlock the last door the hags came out but my barbarian went and opened the skeleton door because chaos. I have one heck of a fight going on.