The children I’ve listed here may be grandchildren of Benjamin and his first wife Drucilla, rather than children of Ben and Sarah. It’s even possible that Sarah is not Ben’s wife, but his widowed daughter-in-law. (It’s too bad the censuses before 1880 do not list relationships.)

The reason I have these suspicions is that Emily Jane married a grandson of Ben and Drucilla, Benjamin Franklin Johnson, son of Zachariah R. Johnson and Delilia Evans. If Emily is a daughter of Ben Sr. and Sarah, then she would be a half-aunt of her husband. But if she is a granddaughter, then they would only be first cousins.

Sarah Amanda’s death certificate, though, listed her parents as Benjamin Johnson and Sarah Moore.

1850 census of Fleming Co., Ky, division 2, enumerated 15 Aug, lists as family #78:
Benjamin Johnson Sr., 74, farmer, b. Va; Sarah, 49, b. Va; Emily Jane, 11; Sarah Amanda, 10; David, 7.

1860 census of Rowan Co., Ky, Morehead P.O., enumerated 4 Aug, lists on p. 40 as family #208/212:
Benj Johnson, 84, farmer, b. Va; Sarah, 60, b. Va; David F., 17, b. Ky.

In 1870 Sarah was listed with Emily as age 70.