The myth of "Lady Grace O'Neill" simply *will not* die and *cannot* be killed. We may just have to leave her attached to Lt. Edward Waters and clearly marked {FICTIONAL}.
Shades of Mary "Littleton" Scarburgh....
Incidentally, watch Colonel Edmund Scarburgh, Il for the reappearance of his Fictitious wife - somebody saw fit to remove or merge her, but that myth is also too deeply ingrained. Sooner or later someone will bring her back....