I think I got a break. James McGee survived the war. He divorced his estranged wife Alzade in 1868. They had married in 1859 and by 1860 were separated and living in different households (see 1860 Census). See James McGee vs Alzade Courtney, 1868, records of the Chancery Court. He divorced her on grounds she had abandoned her household. He died probably around 1871-73.

I believe William J. McGee-- the J. probably for James--- is buried at Rock Island. I believe this because the family history has no mention of James. Only William J. never coming home from the war.