This camp is located at the area that is NW of the zone, and you can get there by going through the double doors on the NW of courtyard and following tunnel to temple, then dropping down to the green orb thing.
The avatar of fear spawns in the green orb, whereas the cenobite PH is the one that wanders around the orb.
The AoF procs that scarecrow fear (a stun) very often and it makes for a long annoying fight. He Ramps, flurries and enrages as well and hits for just under 4k. The Cenobite is a much easier fight since he doesnt do much damage as he is casting spells all the time, but his CHs and promised renewals can really prolong the fight so hope you can stun. He hits for just a tad less than the AoF.
As for the drops, the Othni armor seem to be random, 50% drop rate on the named, but the trash can drop it as well, rarely. As for the mob specific loots, The Trinket seems to be the common drop on the AoF, belt being uncommon and weapon is his rare. (so far 8 trinkets 2 belts and no weapons). As for the cenobite, both drops seem to be equal in drop rate (so far 5 weapons and 5 augs).
Repop time is about 15min.