I would say the entire political leadership of the Confederacy should’ve swung from the gallows. All of those who instigated secession, and all of those who had made the decisions to fire upon Fort Sumpter thus starting the war - hung.
The Generals and military leadershp would have been reviewed on a case by case basis. Those who fought out of love of state, rather than hate of the Union or love of slavery, could be re-habilitated back into society after a time and could act as guiding forces to help heal the anger of the broken South. They could re-earn their citizenship and their honor by helping heal the country.
Those who fought with the aim of keeping slavery alive forever - hung.
The grunt soldiers were boys fighting to defend their homeland in most cases. Their homeland already suffered enough with Sherman’s marches. I would grant a conditional amnesty to the boys who fought - any boy under age 35 or so. They would have to renounce, in the eyes of God and before the law, the Confederacy, Slavery, and would have to swear an oath to the United States and to work in congress with the North to re-establish stability.
If they renounced the Confederacy, Slavery, and swore an oath to the Union, they would be re-admitted as citizens, with no ill-will or malice. In the cases of boys who had been Union troops prior to the War, they could be reactivated as Union troops with their original pre-war rank and all benefits thereof. That is only IF they accepted the oath and renunciation clause.
Any who refused to denounce the Confederacy, or denounce slavery, or refuse an oath of allegiance would be imprisoned and sentenced to terms of hard labor.
The South would remain a Federally occupied zone with no true rights until the last soldier who fought for the Confederacy died. The government of the South would be regional governors appointed by the North who would institute equal rights. Only after all remaining Confederate soldiers had died of old age would the process of re-admitting the South into the Union.
Re-admisssion to the Union would require, first of all, a review of the conduct of each state on a case-by-case basis over the course of occupation.
Afterwards:
- A vote on the part of each Southern state to rejoin the Union. If they voted “no”, they would remain a federally occupied territory.
All states who voted “yes” would proceed to Step 2:
- All states who voted to rejoin the Union would have to answer a referendum as to whether or not they denounce the Confederacy, slavery, and support equal rights. A state would only be re-admitted if 75% of the state affirmed by vote that they denounced the Confederacy, slavery, and supported equal rights. This referendum would be a multi-step process (similar to the process Puerto Rico is taking to attain citizenship - very clear, very concise, very clearly worded)