Much depends on if the nature preserves followed a heavy demographic collapse or the places were forcibly depopulated.
If the former, the question is why the population contracted hard enough for the U. S. to give up on the state structure....
Spain may be in bad enough shape that it cannot actively help much if at all in terms of troops or wealth, but friendly ports/safe havens/eventual staging area for Continental Landing would be rather likely especially with the odds of a Nationalist Government In Exile ready for installation if...
Considering how much of the Red Army would be in Spain at that point (i.e. none) it would be far more likely that there would be an open break with Moscow over this (along with at least a few of the international Communist Parties following Madrid).
Any iteration of Republican Spain also just...
And quite possibly a bigger England-screw as well, in terms of reducing the offshore areas to a neglected backwater taking hind-teat to ambition or even basic defense on the continent.
ETA: For that matter, the 'defrancification' of the Angevin ruling classes (to the degree that it even got...
You are aware that the pre-revolutionary French Kingdom included places like this? I am certain the death toll on the various Sugar Islands topped 150 per day, so the concern of how much worse the Reign of Terror was might be mistaken for who was dying.
Ongoing anti=Union violence would be the sort of thing that accelerates meaningful enforcement of Amendments XIII-XV (the re-imposition of Jim Crow was considerably bloodier than the Watts Riots, let alone '92). The blacks of the low country and the hillbillies of the uplands becoming the...
IIRC two of these cases involved a distant metropole enforcing their dictates and the third was the unpopular edict of a monarchy which got them overthrown. The CSA is not in the same boat as either and unless/until DC or London has them by the economic short hairs they never will be.
Also...
On the Ottoman Realm: To what degree do they manage to maintain use of the pre-Ataturk script/language in popular/everyday usage? It is improbable that the languages do not diverge but trade/communication will lead to some bleed-over.
Come to think of it, the same question can be asked about...
One does wonder how many regard Yiddish speakers as "cheating" when they learn German. I mean once one gets the script down....
OTOH, the Eastern Slavic languages are not that divergent either.....