It should be known that in statue form the Drow are vulnerable to force damage.
I have my Warlock go through and blow them all up without waking up the Spectator.
The fight is decidedly easier when the Spectator is by themselves.
The very first time I stumbled on this fight my rogue was exploring ahead. I immediately ran away and hid in shadows and the Drow eventually saved versus the spectator's charm and killed him leaving me to only have to fight the two remaining Drow.