Thanks very much, George, for the detailed answer. I had not seen the lieutenant's report. In the Independence County (AR) Chronicle , a quarterly of the historical society, Oct. 1975, a usually very reliable researcher says on pg. 3, "Seldon M. Weaver enlisted in Captain Gibb's company. He was wounded in the battle of Wilson's Creek. He recovered and went with his company and was killed in action near Atlanta on Aug. 18, 1864." Unfortunately, he did not give his source.
Seldon's three brothers and his sister were in the Confederate service. His sister, age 16, was picked up in St. Louis, in June of '64 and tried, convicted and sentenced to death as a spy - later reprieved. She and another of her Confederate brothers took Seldon's name after the war. She used Seldon as her middle name the rest of her life. I can't quite see her doing that if he were a deserter. Since she was in special service, might he have been, too? I don't suppose there is any way to check that possibility.