I've just started working on this family for a friend. She is hoping to find information about medical histories.
My friend's grandmother was Bertha Sykes, who was a sister to your Milton Sylvester Sykes. Bertha also married a Cupit, and I would guess it might have been a brother of your Mary Jane Cupit; but that's just a guess. Bertha married 2nd some Chappell or other who adopted her Cupit children from her first marriage (Earl Mayo and Susie Lee Cupit).
If I have the census information straight, all of the children of Melissa Cupit and Charles Sykes were born in Mississippi except the last one, Vella (pronunced VEE-ella), who was b in Louisiana.
Do you happen to have more information about this line, such as which Cupit Bertha Sykes married? Would you have any death certificate info for any of the Charles Sykes-Melissa Cupit families? Are you aware of a Cupit family reunion that is held each year, I think later in August, and in Arkansas, for descendants of these families?
Will gladly share census stuff, or whatever I have that might be of interest. Can find out from friend exactly when & where the Cupit reunion is held if you are interested.