i had the same issues. managed to murder the goblin priestess by silencing her and being stealth about it, but then you can't just get rid of that guy without aggroing the entire goblin pack.
sucks because the game specifically says "you dont need to kill everyone, but only get rid of the 3 bosses, after that, the goblins will sort themselves out"
but this doesn't really happen.
Did you destroy the 2 war drums in that room and the one war drum outside?
