Probably not (General McPherson was planning to marry when he was killed and doesn't appear to have had any children), though some here would like to see his namesake come to the same end.
I think the 1870 census is believed to have a larger-than-usual number of people who were missed. My great-grandfather was 9 years old in 1860 and somehow got listed twice on the 1860 census. I think he may have been missed entirely in 1870.
There were probably many men who died not long after the war from ailments contracted or wounds suffered during their military service, but I don't know how well they are included in the statistics.
Probably not (General McPherson was planning to marry when he was killed and doesn't appear to have had any children), though some here would like to see his namesake come to the same end.
Two of my great-great grandfathers served throughout the war from the ages of sixteen to twenty. One of them, Sebastian Boehler, died real young, in his early fifties, as a result of the exposure he suffered during the war.
Thankfully, he did live long enough to have a family...or I guess I wouldn't be typing this message! :-)