The CSA had no right to order American troops out of their fort. It doesn't matter if they gave them four weeks or 99 years.
The North was offering the South a constitutional amendment protecting slavery in the south. The South rejected this, and chose secession. It's pretty clear that they were not a rational or reasonable people.
That's basically what I was getting at. Why did the Southerners want them to leave. Calling them unrational is the easy answer. But there must have been some reason. And this is the first time I've heard about any proposed amendment that would have allowed Southern states to keep slavery. If it did happen, it must be that it didn't stand a chance in hell of passing. Otherwise, why would the Southern states choose war. Maybe it was for the same reason that there was an American revolution. Because the Southerners didn't like being taxed. Who knows. Not me.
All that aside, I have written other threads that nobody will comment on. It kind of makes me wonder why you are doing so here.