If this has already been addressed, I apologize, please send me off in the right direction. I read in a few places that there were soldiers that fought with him in the Civil War and later ended up with him in the Indian Wars, but I am having a hard time identifying who those men were. Thank you in advance for the help!
I have found only 2 EM who may have served under Custer.
Pvt Lynch of Co F was a member of the 8th Ill Cav. That regiment was a long time unit of the 3rd Division of the Cav Corps of the Army of the Potomac, the division Custer took command of in the Fall of 1864. However long before then the regiment accompanied its colonel, William Gamble, to Washington DC. It was apparently the practice for regiments to transfer with their colonels. Lynch said he served with Custer. Since at least one officer of the 8th Ill remained on the division staff, it's possible some enlisted men remained on detached service at 3rd Div HQ.
1st Sgt Winney of Co K may also have served in a regiment that was definitely with Custer's Division. This was the 2nd NY Cav. In the roster of the 2nd NY Cav I found a Dewitt Winney about the same age and from Saratoga Springs NY. .
There may have been a third EM, but I can't remember and will have to check.
Custer's brother, of course, served on the Div staff, and Capt Yates, as Gen Pleasaanton's ADC, accompanied Custer on the Charlottesville Raid in early 1864. Three or four of the 1866 officers also served under Custer, but only Capt Barnitz lasted beyond the regiment's 1st year.
On the Charlottesville raid Custer command men fro the Reserve Brigade which usually made up of the Regular Army cavalry regiments and some serving with the Army of the Potomac and some Volunteer regiments like Rush's Lancers and the 1st NY Dragoons. In addition to the 1st, 5th, 6th, and 7th, Mich the Michigan Brigade 1st Vermont and 25th NY served for periods of time with the Brigade. The regiments of the 3re Div while Custer commanded it were the 1st NY (Lincoln), the 2nd, 5th, 8th, 15th, and 22nd NY, the 2nd Ohio, the 1st, 2nd, and 3rd West Virginia, the 1st NH, 1st Conn, 1st Vt, 3rd NJ5 and the last 2 remaining companies of the 3rd Ind. So anyone wishing to look for members of those regiments have their work cut out for them.
Thank you for your thorough response! I appreciate you shedding some light on my question. I was under the impression it was a more significant number so this is very interesting information. If you do find anything more, of course, I would be interested in hearing about it. Many thanks!