Almost any Caucasian women could play similar roles
Go back and read race history in the United States and you'll learn that women who were 7/8th's Caucasian and 1/8th African were indistinguishable from full Caucasian women; called, 'octoroons', an archaic term, considered offensive today. 3/4th Caucasian and 1/4th African women were called, 'quadroons'. Many years ago, an Afro-American colleague gave me a quick race history lesson about this. He claimed that in the old Deep South, in places like rip-roaring, fun-time, Sodom and Gomorrah - New Orleans - slave owners deliberately 'bred' such women in what sounds to me a creepy version of eugenics twisted in with animal husbandry cross-breeding. Evidently, the old white plantation slave owners discovered this per chance after interbreeding with their slaves and then their sons or other white men interbreeding with the mulatto offspring of the first interbreeding. If you're already offended and disgusted, don't blame me or call me racist... I'm just giving you all here a lesson in the dark side of American history.
The late, prolific and talented Afro-American oil painting master, Archibald J. Motley, Jr., wrote that octoroon women could be fair-complexioned, blue-eyed blondes.
I remember the horror movie, CANDYMAN 2, where the blue-eyed, blonde heroine, learns that the insane, vengeful revenant, Candyman - formerly a black man in life - is her ancestor, making her either an octoroon or more white, called, a hexadecaroon. Back in 2002 I met a young, white woman who nonchalantly told me her ethnic background which included four or five different Caucasian ethnic backgrounds and then, Afro-American. I would have never known had she not told me. Heck, she could have made the whole thing up.
My point is, almost any Caucasian actress could play the role of a octoroon. For a quadroon, perhaps a brunette, dark-eyed beauty would be best. Examples of brunette, dark-eyed white women - not necessarily part black - include the late Natalie Wood, Selma Blair, Sela Ward, and Jennifer Connelly. Only the most fairest of Caucasians, like the pale-skinned, redheads of Scotland and Ireland could not convincingly play such a role.
I once met this dude in which I can honestly say that it would have been not totally accurate to describe him as black, neither, white. He had brown skin, on the lighter side. His curly hair was a mixed pigment of light brown with reddish and yellowish highlights. His eyes were an unmistakable, green. If I were a movie director wanting to film a science fiction movie in the futuristic United States, I would hire this guy in a heartbeat, to demonstrate the possiblity of continued interracial mixing.