First of all, this most likely is NOT the fault of the Xan NPC mod. Secondly, the reason I'm posting this here is to warn people of this incompatibility I ran into. I'd have posted it at SHS but for some reason their forum is currently down.
Here's the problem I ran into. I was already in the middle of a game, with Xan in my party as a Wild Mage. (I'd used the installer to change his class.) I decided to give Refinements a try because I wanted to try out the new HLA's as well as nerf Weimer's "overpowered" Shapeshifter Rebalancing. When I loaded my savegame, at first it looked like everything worked out okay. The paw items from the existing rebalancing mod were still there, but the special ability worked the way it was supposed to.
Then I took one look at Xan's inventory and realized everything had gone to hell. Almost all of the items on him, except the Robe of Vecna and his Moonblade, were redded out. His class was listed as "Mage" because Refinements apparently didn't know what else to do with him. Yet even so, the wands, belts, jewelry, etc. were all unusable. I have no idea what class the mod tried to change him to or even why it tried to overwrite the changes that the Xan mod included.
I uninstalled Refinements and it worked fine once again. I essentially found out the hard way that any NPC mods should be installed
after Refinements. I suppose I could revert to a clean installation (again) and test changes to the install order.
Edit: I just finished the test. I rolled back my mod installations, installed Refinements first, then reinstalled Xan, and then tried loading my savegame. The problem did not occur this time.