It is true the sout sent their 'negotiators' to discuss the debts of the south, and they were refused, but primarily because the debts of the South were, even before the south stole every bit of Federal property not nailed down, so much larger than it's ability to repay them that meeting with the commissioners could only be the equivalent of a bankruptcy sale. Compared to the southern democrats and their penchent for soaking down 60% of the Federal treasury funds annually while the south only contributed 14% of the tax income, Lincoln was indeed a real conservative. It is to be noted that while the south had a way to fund it's war effort, it failed to do so and simply ran itself into a financial hole in the ground. The north, on the other hand, managed it's resources very competently dispute what was then an un-magineable debt load. THe credit for this did not go to Linccoln though, but the Thaddeus Stevens who was head of the House Ways and Means committee for the duration of the war.
Long trashed in cheap pulp fiction and, most notably, Woodrow Wilson's dixiecrat brutally racist history of the war, Stevens was truly appreciated and acknowledged in his day, and was given a public viewing on the same bier in the under the Capital Dome that Lincoln was given. He was a truly remarkable individual and a political wit of true genius. There has been no American politician like him since, and given the way the ideas of the founders are being run into the ground, very likely never will be another.
You can see the wood stand that held Lincoln's casket for his viewing at the Capitol if you know where to go. I believe it's in a hallway off the side of the gift shop, in a roped off area, down the stairs. A security guard can escort you, though I'm sure security is much tighter these days.