I think I've already answered my question. But I needed a longer form than the profile comments to write out my conclusions. And the G2G forums seemed like a good place to do that.
A merge proposal made me curious about women name Sarah E. Chronic, so I did a little digging. I learned that there are not one but three Sarah E. Chronics born in Edgar Co., Illinois around 1850.
Here's what I learned about the women:
Chronic-7, daughter of Adam and Susan Chronic, was born around 1842, because she was 8 years old on the 1850 census. Sarah E. Chronick married Dudley Downs in Edgar Co. in 1860. On the 1860 census, Sarah and Dudley are living with Dudley's parents, just two households away from from Sarah's parents, Adam and Susan Chronic. Sarah is 18 years old in 1860, which matches with that 1850 census age. So it looks like Chronic-7 married Dudley Downs.
Another Sarah E. Chronic - Chronic-13 - was born around 1847 in Edgar Co., the daughter of Samuel and Elizabeth Chronic. A Sarah E. Chronic married William Huckaby in 1859, and I believe that was her. They had a son, William Huckaby, who was born around 1861. (I know this, because William's parents' names are listed on his marriage license when he's an adult.) I can't figure out what happened to his parents, but I found 19 year old William Huckaby living next door his grandparents, Samuel and Elizabeth Chronic in Clark Co., Illinois in 1880.
So that just leaves Sarah (Chronic) Wilhoit - Chronic-2. I think she was the daughter of David Chronic - Chronic-14 - and Eliza (Hicks) Chronic - Hicks-10436. They had a daughter, Sarah E. Chronic, born in Edgar Co. around 1850. I believe she was the Sarah E. Chronic who married Robert Wilhoit in 1867. In 1870, Robert and Sarah (Chronic) Wilhoit are living right next door David and Eliza (Hicks) Chronic.
So I think Sarah (Chronic) Wilhoit was the daughter of David and Eliza Chronic. Of the three Sarah E. Chronics, she's the only one with an 1850 birth year, and she's the only one who lives next door to David and Eliza as an adult.