Option 1: Do nothing. The war is over and the South lost, and so these formerly seceded states should be allowed to rejoin the union as is, though they must accept the 13th Amendment.

Option 2: Anyone who takes a loyalty oath is pardoned. No pardons for high Confederate officials and persons owning property valued in excess of $20,000. States must abolish slavery and repeal secession ordinances, but not give voting rights to freedmen, before being readmitted.

Option 3: General amnesty to all who pledge loyalty to the United States and pledge to obey all federal laws pertaining to slavery. High Confederate officials and military leaders are temporarily excluded from the process. When one-tenth of the number of voters who had participated in the 1860 election take the oath within a state, that state can launch a new government and elect representatives to Congress. Rebels' property is to be restored. States' boundaries, constitutions, and laws (except those relating to slavery) will be preserved; neither freedmen suffrage nor confiscation is required.

Option 4: The President appoints provisional military governors in the seceded states. When a majority of a state's white citizens swear allegiance to the Union and swear an "iron-clad oath" never to have voluntarily aided the Confederacy, a constitutional convention can be called. Each state's new constitution must abolish slavery, repudiate secession, disfranchise high Confederate military/political leaders, and repudiate Confederate debts. Criminal laws, including habeas corpus, apply equally to whites and blacks; otherwise, state laws prevail. After a majority of state voters, the President, and Congress approve each constitution, elections can proceed. No provisions for freedmen suffrage.

Option 5: Confederate leaders are traitors. They should be put on trial (which, let's face it, is not going to be really suspenseful), then hanged or shot for treason. The seceded states should be completely rebuilt on new, just grounds that protect civil and voting rights for freedmen.

Actual punishments:

Confederate President Jefferson Davis spends two years in jail, with chains around his ankles and no book but the Bible for the first year, after which he moves to Canada, sells insurance, is elected to the Senate in Tennessee (which he can't be), and turns down the presidency of what would become Texas A & M. He then writes a 550-page book called A Short [!] History of the Confederacy and a history of the war before dying in 1889. He has his citizenship restored in 1978.

Confederate Vice-President Alexander H. Stephens spends 4 1/2 months in jail, applies for a pardon, June 1865; elected to US Senate in Georgia, 1866, he can’t take his seat because he can’t sign the oath vowing not to have helped the Confederacy; after Andrew Johnson grants a general amnesty in 1868, he's eligible for office. In 1873, he's elected as a Representative (through 1882); he's then elected Governor of Georgia but dies 4 months into his term, in March 1883.
Robert E. Lee 's application for reinstatement is lost and not found until 1970; citizenship rights restored 1975

The national debt in 1860 amounted to $2/person. Had the federal government bought and freed every slave in 1860, it would have cost $2.7B over 30 years--about $7.25 per person per year. The war itself saddled every American with the equivalent of $75 of debt per year.