Aumriel has an elven name and an elven lifespan, and wispmothers do have elven features. Could the Pale Lady encountered in Frostmere Crypt be the lich of a Falmer warrior-queen who resisted the Nordic incursion into western Skyrim, and does that mean that all wispmothers are also remnants of the Falmer? Here's the excerpt from the book...
For generations, the people of Morthal have told whispered tales of the Pale Lady, a ghostly woman who wanders the northern marshes, forever seeking her lost daughter. Some say she steals children who wander astray, others that her sobbing wail strikes dead all those who hear it. But behind these tales may lie a kernel of truth, for ancient records speak of 'Aumriel', a mysterious figure Ysgramor's heirs battled for decades, and finally sealed away.