you seems to be ignorant to simple fact, that the night offer protection only around the anchor. if the pets are ranged and stay outside of it - they will get ripped.
Darkest Night is -tohit and - damage debuff. This means that when you place it on the anchor, all the enemies near the anchor are less likely to hit you and do less damage when they do. It's effects have absolutely no relation to the position of you and your teammates, and everything to do with the relation of the anchor to the rest of the mob.