My Drakkin necro went through the factioning to be able to do this quest.
Using Essence of Iksar potions to check faction as I killed many bandits in Warsliks over several days:
Dubious and Indifferent would not work. He would just give me back the brains.
Amiable worked.
Once you /con amiable with illusion on you can repeatedly tell the iksar Hermit you are a great sorcerer. This still gives faction hits (many report it does not)and took me to warmly while in illusion.
The parts of the tapestry you need for the second rank skull cap drop off the sarnak hatchlings as well, so make sure you loot them as you see them. They are lore and must be sewn together with tailoring.