Went down here the other night to get some armour for my newb SK. Here is the info i accumulated over the night. (69 necro)
All mobs huge magic resists, my drains landed, and all my fire spells landed no problem, everything else resisted
Sentries: conned grey/green
Lots and lots of different spells dropped off these guy, like the spells that drop off of named spiders in velks lab (lvl 50ish spells)., hands and feet of armor dropped a lot as well (prolly 10 pairs rotted after i got my first set)
Sentinals: Conned green/light blue, Summons (at least some do)
Lots of spells of these guys too, arms were their more common drop, only got one bracer the entire time i was there.
Watchers: Green/light blue, summons
spells again off these fools, legs and BP, legs dropped about 3/15 spawns, got one BP after about 4 hours of killing from zone into where the councilers are, was the last peice i was after so i took off once it finnaly dropped.
So if you comming here for the no drop armor like i was, shouldnt take you long to get hands and feet and hat (dont remember which ones dropped hat, but saw quite a few of them too) Bracers were rare (i still need one but didnt feel like staying longer) and BP ultra rare off of their respected mobs.
and just FYI, i pulled all the summoners with lvl 1 lifetap... this allowed me to pull to safe area without being summoned, and for some reason with the lifetap, other greens and light blues would not aggro my pulls, so i was able to single pull the watchers. but with higher damage spells/dots I would aggro everything around them at the same time.