These names are found in the National Archives index to military service files --
No one knows how many Confederate soldiers died during the war. Service files and pension applications may include that information, but many do not. The information was either never recorded or destroyed or lost.
Nancy Brown appears on the 1870 census of Alabama, living near North River with her family. She eventually applied for a pension in the name of George W. Brown as a resident of Tuscaloosa County.
Mary A. Cain appears on the 1870 census of Texas, living near Waxahatchie with her two daughters. Since the youngest is four years old, it suggests that the child's father was living in 1865. You could check the 1866 state census of Alabama for William Cain's household.
Copies of military service files and pension applications are available here --