Incorrect. Lincoln admitted that there were rebel representatives in town to deliver the Southern ultimatum; they were not there to negotiate anything but capitulation to Southern demands.
The details are irrelevant because Jesus Christ himself would have been turned away by that blood thirsty goon President from Illinois.
I don't see Jesus Christ taking part in the rebel contingent, a group without any peaceful intent whatsoever.
My guess the ultimatum in a nutshell was "we are leaving so leave us alone". If Lincoln really wanted his island fort in the middle of the Cooper River that bad, then 600,000 dead was the price of his stonewalling....