A few years ago, when my siblings Jim and Genevieve went with me to the Audrain County Historical Museum, we found a book of Mexico Veterans. My dad (William Thomas Fecht) and Uncle Jack (John David Fecht) were listed as WWI vets, and connected to Patrick Walsh also listed as a veteran. Patrick was their maternal grandfather. Their mother Elizabeth Ann Walsh was Patrick's daughter.
Patrick Walsh, husband of Ann Finn, was born in Cork County, Ireland. He married Annie Finn (I think) in New York City. There are a zillion Patrick Walshs who came through New York City.
He is buried, as is Ann Finn Walsh, in Calvary Cemetery in St. Louis, Missouri.
There are about 6 Patrick Walshs who were part of the Confederate volunteers in St. Louis.
If I lived in Missouri, especially near St. Louis, I would take up the whole Walsh puzzle. Calvary Cemetery is, I guess, a huge place. but, I have some decent leads for anyone who might want to play detective here.
Aunt Florence Sullivan, Patrick's grand daughter, often said that "we had family on both sides" of the Civil War. Uncle Jack (John D. Fecht) had a sword with the letters CSA on it, but it disappeared when he died.
The Walshs lived on the top of a hill in Saint Louis that is now the Italian district. The Catholic Church in that area might have marriage, birth records of Elizabeth Ann Walsh and Hannah Walsh.