I just checked out Erdman in the National archives. There are over 21 entries (a lot) on him ie: musters, requisitions, bi-monthly reports etc. In all he is in CO. E. So this eliminates him. No I think the error, if an error, occurred when Edwards enlisted, for a brief time, in the 2nd KY Infantry (later mounted) in 1861. He soon "jined the cavalry".