Not much information is given in the books but the Congaree Socialist Republic was a junta under the control of Cincinnatus with a small group of lieutenants. There really isnt enough info tho on how they worked to really compare it to stalinism or moaism.
Given the general illiteracy of most Confederate blacks, I wonder if there could even be distinct ideological currents before the war ends. Most of their literature would be stuff smuggled in from the north and reprinted in clandestine presses. The other wildcard is the impact Lincoln had on anglophone Marxist thought—they are mentioned as reading some of his work, so it’s possible they espouse a Marxist-Lincolnist doctrine with no analogue IOTL.
Both Stalinism and Maoism in large part are products of the specific Russian and Chinese historical experiences. The same will hold true in any Black Socialist Republic in TL-191. There won’t be the Gulag and forced labor and secret police obsession that characterized the USSR because they don’t have an Okhrana or Katorga system to model that on, nor the fetish for forced labor that Stalin had (Applebaum characterizes him in ‘Gulag: A History’ as self-consciously imitating Peter I’s construction of St. Petersburg with forced labor). Nor will they have the Maoist military-type rhetoric because they don’t have a Long March or extended war with Japan.
So what will Black Confederate Communism look like?
Heavy emphasis on education, because that was denied to them. Is there even a Black middle class to draw on as a revolutionary vanguard? There will be a strong program to incentivize blacks from the US and the European empires in Africa to come over. White communists too, from the US Socialist Party. Building up a skilled Black Communist class will be the main objective.
Breaking up the plantations and an aversion to cash crop exports. Can something like the Birmingham steel industry (with which the CS will not part, so Alabama won’t be part of the Socialist Republic) be built in Mississippi?
State violence: as noted, camps and secret polices are less likely than in the USSR. Rather, show trials in public squares and executions by hanging or firing squad in public. Mob violence more than Chekist precision.