You said: “They were not there to negotiate, the letter doesn't say they were there to negotiate.?
So, again, your statement is shown to be what it is....a total misrepresentation.
Only after Lincoln caved to their demands and only if the topic was of interest to them as well. Your insistence that it would have included payment of debt and for stolen property is not clear from the letter Davis sent. You can call that 'negotiations' if you want. It was more like a mockery of the word.