Well I only find one William Pumphrey in the 2nd Ark. he is listed as John William M. pumphrey. Most time he goes by Wm M, but in his prisoner cards he refers to himself as John William, all on the same person. He was captured at Chickamauga and within a month joined the Union 11th KY Cav, serving until at least Aug 1864 the date of his last muster, and possibly the end of his enlistment, hence the mo....muster out rolls. There is nothing official documenting his service in any other unit. It is curious why he would go the CS pension when he could have easily obtained a US pension earlier and without any hassle. I believe them to be one and the same man, everything matches up. All the other info, I have no access to in order to corroborate or add anything. If he is buried there and has headstone with Hindman Brigade it all looks right, but lot s of additional info that is not easy to figure out. It may be accurate, may be tweaked a little (these CS vets did look out for one another and sometimes not tell all in th epension applications) but there are some connections there it looks like. Quite the mystery you have on your hands.