Apart from sources like newspapers and census records, the following books contain a great deal of information about these men (ranging from racist opinions of their time to modern understandings), and you will find quotes from them scattered throughout the individual pages.
Behrend, Justin. Reconstructing Democracy: Grassroots Black Politics in the Deep South after the Civil War. Athens, GA: University of Georgia Press, 2017.
Bennett, Lerone. Black Power U.S.A.: The Human Side of Reconstruction, 1867-1877. Chicago: Johnson, 1967.
Cabinis, E. W. The Clinton Riot: A True Statement, Showing Who Originated It. Jackson: Democratic-Conservative Executive Committee, 1875.
Foner, Eric. Freedom’s Lawmakers: A Directory of Black Officeholders during Reconstruction. Baton Rouge: LSU Press, 1993.
Gates, Henry Louis, Jr., and Evelyn Brooks Higginbotham, editors. African American National Biography. Oxford: Oxford University Press, 2013.
Journal of the Proceedings in the Constitutional Convention of the State of Mississippi. 1868. Jackson: E. Stafford, 1871.
Lynch, John Roy. The Facts of Reconstruction. New York: Neale Publishing Company, 1913.
McFarlin, Annjennette Sophie. Black Congressional Reconstruction Orators and Their Orations, 1869-1879. Metuchen, NJ: 1976.
Montgomery, Frank A. Reminiscences of a Mississippian in Peace and War. Cincinnati: Robert Clarke, 1901.
Satcher, Buford. Blacks in Mississippi Politics 1865-1900. Washington, D.C.: University Press of America, 1978.
Thompson, Julius E. The Black Press in Mississippi, 1865-1985. Gainesville: University Press of Florida, 1993.
Thompson, Patrick H. The History of Negro Baptists in Mississippi. Jackson: R. W. Bailey Printing, 1898.
United States. Congress. Senate. Mississippi in 1875. Report of the Select Committee to Inquire into the Mississippi Election of 1875. Washington: GPO, 1876. (Link to Volume II)
Wharton, Vernon Lane. The Negro in Mississippi: 1865-1890. New York: Harper & Row, 1965.
Unless otherwise noted, all images are from the 1874-1875 Mississippi legislature composite, the 1876 composite, the 1878 composite, the 1880 composite, the 1882 composite, the 1884 composite, or public domain books and newspapers. There is also a portrait of some members of the 1890 legislature, but it is unlabeled.
Recommended Sources for Background Information / Further Research
Civil War & Reconstruction Governors of Mississippi
Mississippi History Now: The Mississippi Constitution of 1868
Mississippi History Now: The Clinton Riot of 1875
The Colored Conventions Project
Mississippi Encyclopedia: W. E. Mollison
Wikipedia: Thomas W. Cardozo