A few nitpicks from an otherwise wonderful post
Quite bluntly the whole exercise was a '90s thought experiment, nay basically a political cartoon, commenting about how so many southerners at the time were getting into political power, or something. I think doing things like picking Oak Ridge as their Los Alamos is a real TL-191 type move of having a low butterfly zone where you can just pick existing things in our history but put it on another side, which isn't plausible so much as it can be fun, if done well.
1. Do Yankees move South to take advantage of a better climate and better business opportunities? I'm guessing the CSA is going to be a place full of low taxes, a cheap workforce and with a good climate, they can encourage lots of Yanks to at least summer down in Dixie.
Yeah, even according to
Matthew White's original piece, "President Gephardt wanting to close the US border to the cheap labor of Dixie", though that might also be an allusion to Confederate illegal immigrants. I think it really depends if the two nations have had warmed up relations that would allow for cross-border trade, but I think where the original piece left off- and continued by both
@Fleetlord and by
@Underboss_3- there's a fair amount of animosity remaining between North and South to prevent that. Which I think is fine, because it unfortunately reflects OTL America's current internal issues, though our real world issues aren't divided between regions so much as more urban vs. rural.
Also, this is where the "parallel construction" of the whole experiment kind of falls apart. In the OP, Gingrich/Helms handily trounced Clinton/Gore, so is NAFTA dead? Or do they pass it, since the American Party would likely be pro-business? Or is NAFTA unlikely given continuously simmering North-South antipathy? Though, Fleetlord has POTUS Huckabee withdrawing from the pact, meaning it was passed sometime in the previous decade, which is fine. Also I see he also has Rodham unmarried to Clinton, which means she'll be the frontrunner in 2016, good to know. (I think Fleetlord follows Matthew White's original scheme more faithfully, but I would love to see a continuation along Underboss_3's version as well, since it's also very well written and takes some nice creative liberties. )
2. Is slavery still a thing in 1965, or are blacks just noncitizens? Also, would the South encourage them to move north, or would they keep them down south for cheap labor? I feel like this could be a political divide, with some arguing for a white ethnostate, while some might argue for blacks to stay in the CSA as they would for sure be the backbone of the agricultural economy. Also, might some northerners see blacks the way many see hispanics today, a cheap source of labor but also a source of crime?
As per the original article, slavery was abolished in 1913. As far as the fate of black people, I think the parallelism will hew closely to OTL, meaning they are mistreated and live under systemic inequality bereft of reparations. So basically OTL, except slightly worse and more blatant mistreatment. The original work was a '90s satire, not a dystopia, so I'm not imagining anything too dramatic or Turtledove-shaped. Because, well, modern day America can already be pretty bad.
One can argue that since the legacy of the antebellum South lived on in OTL through sharecropping, Jim Crow, redlining, etc., the CSA Today version of a modern Confederacy wouldn't look all that different from parts of the modern South. Unfortunately, some of the things you're describing aren't too much of a stretch when it comes to poorer black people- the working class is exploited as cheap labor by white business interests and encouraged to leave to the north by the white suburban middle class. They would be de jure citizens but de facto second-class citizens, mirroring OTL issues like overpolicing, voter ID mandates, worse healthcare.
3. What's the culture like? I'm guessing the South's national sport would be football, but would football even reach there if they are separated from the US? Or might they adopt Rugby like the British and French? I'm guessing baseball is still popular too?
4. How would a film industry develop? Sure they would have their own pioneers, but I feel like their film making would be something like the Canadian film industry, where basically it doesn't really exist.
Again, I'm being boring and treating CSA Today as a reskinned version of OTL for the purposes of satire. But I think even if you just take OTL elements, there's still fun with it. The CSA's SEC would probably have a rivalry with the USA's Big 10 as far as college football goes; they wouldn't actually play each other (well, maybe during the years when there's a detente across the Mason-Dixon), but there'd be a big ratings rivalry, also reflected between ESPN in Connecticut and Turner Sports in Georgia. Speaking of the latter, the '00s and '10s will be all about the rise of Hotlanta as the new Hollywood, which has attracted much of the latter's film productions thanks to lower taxes and looser union regulations.