Interesting thread. Offhand, the version of the CSA in David Poyer's novel "The Shiloh Project" is a pretty close runner-up to the dystopian vision of the CSA that is presented in the TL-191 series.
The major difference is that the POD in "The Shiloh Project" is a Confederate victory at Gettysburg and no genocide against the "Conditionally Emancipated" ex-slaves.
However, in that book, the South is a closed-off police state, with barbed-wired fences, guard towers, minefields, etc. separating it from the Union and the rest of the world and life for the average African American in that version of the CSA is, well, not very good, to say the least.
And there is a hint toward the end of a "Final Solution" to the black "problem" in that version of the CSA. It is not suggested to be coming from the CSA government, but rather certain white Southerners who want to "purify" the South.
With guns, ropes, bullets, and fire, among other things.
Like I say, it is not a good place to be if you're black.