I am not sure, but I have speculated that Rector Johnson might be the same as M. D. Johnson who led a company in Livingston's-Pickler's-Piercey's Battalion (which in 1865 was attached to the 1st Indian Brigade under Stand Watie). Shelby reigned in Pickler's partisans in northern Arkansas during the summer of 1864, and issued strict orders for the unit to be properly organized and incorporated into the army. Assuming that this was obeyed (I have not seen any documentation to show this), the unit might have been part of Price's Raid, and since Pickler was killed in July 1864, Captain Johnson might have been temporarily in charge. Much of this is speculation, however, and will need to be investigated further.