Thanks again for all this information, Vicki. I found a great deal of information on Charles B. Johnson and his partner Marshall Grimes in Annie Abel's American Indian as Slaveholder and Secessionist. I believe most of the items you shared from Footnote are this Charles B. or C.B. Johnson.

Charles B. Johnson and Marshall Grimes were partners in Ft Smith AR -- "Johnson & Grimes". Johnson had a contract with the US to supply the Reserve Indians near Ft Cobb in the Leased District, a "reserve" in southwestern Indian Territory that was leased by the US government from the Choctaw & Chickasaw. Johnson was related to Indian Superintendent Elias Rector of Arkansas and, per Abel, got preferential treatment in dealings with the Indian Office before the war. The contract ran out in June 1861 and a new contract was executed with the CSA. Johnson's signature appears as a witness on the CSA treaties with the Seminole and the Reserve Indians. Apparently his role was expanded to commissary agent for the Department of Indian Territory. During the war he made trips to both Richmond and New Orleans.