I think the AB Smith buried in the Brad Cemetary is a different family. Amos Benjamin Smith was born 2 may 1849 in GA and died 13 Jan 1935. He was buried in Throckmorton 14 Jan 1935. He may not have a headstone, as there is no cemetary listing. I have his death certificate. So far, I have been unable to find a date of death and place of burial for Lucinda.
Lucinda's father, Andrew D. Chambless, seems to have died 1860-1870. He is on the 1860 GA census, but he does not appear on the 1870 GA census with Milly and family. There is a Civil War record for an Andrew Chambless who disappeared, and I feel it may be he, but cannot confirm it.