I know this is a long shot since this post is from 2013, but did you ever come across the rest of her children's names? My great-grandmother's name was Allean Douglas and all I know about her is her marriage to my great-grandfather Charlie McMillan and the children they had. I know little to nothing about her parentage. I only have a picture of her father, who is a white man, but no name with the picture. I was told that her father or someone in the immediate Douglas family worked in the sheriff's office in Cheraw.
I hope this gets to you and hopefully we can share information.