That is interesting.Thank you for the information.
I do not show record of a Vansant or a Nancy Addy born in 1819 at all.I would assume she was born in AR and moved to Bowie much later.The fact that they were in Bowie County around 1890 makes me suspect that they are part of the William/Thomas Addy line.
The first Addy I can find record of in Bowie county is my gggrandfather, John Addy (b 1848 in Arkansas), listed in the 1880 census.He and his immediate family are the only Addys shown in the county at that time.No Addys are listed prior to 1880.Nancy may have come from a later migration of another part of the family.
Nancy being 30+- yrs difference in age is a challenge to fit into the picture.
What a puzzle!I would love to know more if you have any additional information.