Fascinating stuff - thanks.
Per the Ava biracial thing, this is pretty OT but one idea I once toyed with when considering how to possibly bring the Grays/Halls back to OLTL was to have the secret an aged Carla was carrying (and hiding from a new generation of Halls) be the shocking truth about the Lords and Llanview: That Victor Lord had somehow stolen Sadie and Carla's family's birthright or fortune, and that the Lords themselves were descended from a member of Sadie's family, making them biracial(!) and making the Grays kin, thereby tying them inextricably to the heart of the show.
I opted for something along those lines vs. the more obvious angle, which was that Victor and Sadie could have had an affair long ago; I felt that played into too many old racist tropes about the rich white man and the black servant, especially with Victor having been revealed to be the kind of monster he was - I felt Sadie Gray would never have been with him.