An absolutely none of that would have happened if the southern states hadn’t rebelled. A Presidents powers are vastly increased during a war/rebellion. If the south hadn’t seceded they still had enough power in congress to stop any republican move against slavery. That wasn’t good enough for them, they wanted their own country where slavery would be the cornerstone that the country was built on. Where it was explicitly protected and enshrined.
Southerners had had that since 1776. In 1860 they wanted more: elimination of confiscatory taxation and protection from northern financed murder raids.
What does that even mean? The United States of America had slavery in every state when it was founded. One of the complaints against George III in the Declaration of Independence was that he was fomenting slave revolts.
You guys keep trying to split hairs between the legal slavery Union and legal slavery Confederacy, and there really is no compelling argument to be put forth from that direction.
The UNION was a legal slavery Union for four score and seven years. In fact it had slavery longer than the confederacy, and only gave it up through Dictator control and constitutional trickery.
Without committing illegal/immoral acts, they could have never gotten rid of slavery in the 1860s.