Having learned that Stillwtaer Reflections in Arcstone (a "summoned" mob brought into being by Mistwalkers)drop Elaborate defiant gear occasionally, I figured I'd better loot these. Sure enough after running the Special Delivery task a few times, I have looted:
The one that had the longsword displayed it, and apparently the extra hp's it added were enough to defeat the Delivery Facilitator, as it walked slowly away while its companions all were nuked
I think I fingered this out. If you catch the ones that dont get killed and start wandering away, they probably are equiping something that gave them the extra HP to escape the rod's AE... Assuming that you dont happen to crit that particular tiny worg.
PS, he dropped Ornate Defiant Cloth Gloves for me.
"a tiny worg" conned grey to lvl 65, so lvl 40 seems to be realistic. The 5 of them couldn't hurt a self-buffed 65 Bst much, only went down to about 85-90% of health until they got despawned by right-clicking the Delivery Facilitator.