Arleigh
Yes I concur that the CCHG Ben Simpson is the gentleman from Kansas. He is listed as 25 years old when he enlisted in the CCHG in Leavenworth KS. That matches his birth year of 1836.
The 3rd MSM fellow could be a number of folks but I don't think its either ben Simpson from Bates or Knox Co. Maybe a fellow from Gasconade Couty thae came from Indiana via Illinois.
John R