William Strother McNeil 1837-1904 here is the find a grave entry with a contemporaneous obituary.
The history included an antebellum history of working the shipping industry with Albert Sidney Johnston later Confederate General killed at Shiloh. He is listed as serving with his father in his MSG Company and returning to the family farm after 8 months service which is consistent with previous posts and history of John Hanson McNeil. Interestingly the obit also relates that he then served in the Enrolled Missouri Militia.
His service card in Co B, 4th Reg't. EMM is here: https://www.sos.mo.gov/Images/Archives/Military/s00819/s00819_0196.pdf
and here: https://www.sos.mo.gov/Images/Archives/Military/s00819/s00819_0195.pdf . The latter card documents a full 8 months service as related in the obituary. He appears to have remained in Daviess County post war and flourished to be well respected.