So, I am not sure which protection plugin is used on the servers here, but the custom NPCs for AG Skies 2 are gone from the End, Last Millenium, and Nether. (and the on island one of Jaded doesn't appear as far as I can tell.) Can a copy of these and other Custom NPCs be loaded on like a neutral island or admin claimed place in said dimensions where people can go to trade with them freely without someone else Safari Netting or golden lassoing them? (So, protections to trade with, but not kill). I don't know if this is possible even based on the protections used, but I am pretty sure PEX allows it. Sidenote: There is a newer version of Ag Skies 2 on Jaded's dl page that is 3 days old now that hasn't been switched to that fixes a bunch of misc bugs.
oO, I didn't even know about them. It could be that they didn't even spawn due to the existing worlds. Anyways as you mentioned they would need to be protected. Do you know what they trade? Is it like the one in the end trades better stuff than the one on the island it self?
There is a JadedCat NPC that shows up in your house if you have the Morvy Cottage or one of the other custom maps, and she trades generally AE2 stuff with some randomly generated loot to boot. (I think it depends on where in the questline/your own reputation is at?) There is another one in the Nether which I haven't seen yet, but I think does some blood magic and thaumcraft things. I don't honestly know what the Last Villager trades in the Last Millenium though. But yeah, they give out quests.