Bless you for not using the words Civl War and using the correct term “War of Northern Aggression”. It was not a civil war. The South had become an independent nation when it was invaded by another country.
As a Floridian, I don’t think the Conch Republic ever actually really intended secession—it was more of a publicity stunt. But I do believe that the South was improperly forced into rejoining a union...certainly not the Union from which they seceded, which died when Lincoln suspended habeas corpus by Presidential fiat.
No, it was a rebellion.
The South had become an independent nation when it was invaded by another country.
No it did not.