Slavery was no longer economical when the Civil war started, it would have ended very soon on its own, with Negroes sent back to Africa. The war was about the Federal government not treating the south properly on tafriffsand taxes.
1) Slavery was the very foundation of the South's wealth. The worth of slaves in 1860 was many millions of dollars. Slaves were worth more than all railroads, factories and other businesses combined.
2) There were some ex-slaves who returned to Africa. I think they went to Liberia. The majority of them stayed in the USA.
3) The war was about the expansion of slavery. The South wanted to spread slavery to the new territories that were opening up, the North did not. The South also was afraid that if Lincoln was elected President he would take away their slaves. Their livelihood depended on slavery. So...in April 1861 they fired on Fort Sumpter.
So, your entire post is WRONG!