I think it is silly to start this with 50 sovereign states wanting to be independent and separate. There are some natural alliances just waiting for a chance!
Remember that Texas was part of the original Confederacy. I think much of old Dixie would be glad to confederate with Texas again. Therefore I do not see an Alabama-Georgia-Carolinas merger without Texas, Louisiana, Arkansas, Mississippi and Tennessee.
Texas could even lead. It’s good.
Florida? Split. The New Texan Confederacy takes the top Spanish moss part. Maybe Oklahoma would willingly join. Perhaps southern Virginia, Kentucky and West Virginia.
From that, the Texan Confederacy would already be the winner, or at least sooner rather than later.
Cuba would be hard pressed to resist occupying southern 2/3 of Florida.