Yes, I familiarized myself with the historical Virginia Dare after encountering these stories and TV shows but I've been unable to trace the origin of the depictions of her as being a witch (unless one of the media I cited is the origin, which is possible)
Apparently in 1837 Eliza Lanesford Cushing wrote an article for a womens magazine that claimed that Virginia had survived Roanoke and how her "
fair skinned beauty dazzled the swarthy indians, but Virginia remained chaste, keeping their uncontrolled passions at bay." This apparently spawned a whole series of legends about the fair Virginia surviving in the North Carolina wilderness, it then intersected with weirder theories about Roanoke (the people where taken to Fairyland, or by demons etc) and u
nfortunately 1830s race politics where "the first english baby born in the new world" became a symbol of America's '
Anglosaxon identity".
Even the more likely story that the Roanoke community found refuge with the Croatoan tribe on a nearby island gets twisted with claims that a evil shaman fell in love with Virginia but she rebuffed him and in revenge he changed her into a white deer - which can still be sighted today.
Theres also a 1908 novel that posits that Virginia Dare was the mother of Pocahontas.
So Virginia Dare is a survivor of a 'mysterious' (p
ossibly supernatural) disappearance, has uncanny beauty and skill, remains 'pure' despite the lusty natives, and is celebrated as a pillar of "Merican" identity. - theres a whole lot of American colonial folklore weighing upon the baby girl from Roanoke.