Bard has a point. The Dark Elves of the Scarred Lands, they don't like spiders. They are underground yes, and fight dwarves BUT they aren't spider worshipping socio-paths from Faerun. They orderly, intelligent AND they work well together to make new and more interesting things with tatoos and golems/constructs.
That said, I don't see why you COULDN'T use Queen of Lies in a Scarred Lands campaign, but Xarlen, the module ISN'T SL based in anyway. The Serpent in the Fold will be, since it will be a SL adventure but doesn't mean you can use some of the elements in that adventure in another world.