Stephens may just have had an incentive to "spin" what happened at the conference. All reports I have read, with the exception of those quite obviously trying to be Confederate apologists, agree that Lincoln's terms were: reunion, acceptance of emancipation, immediate cessation of hostilities, and the disbanding of all Confederate forces.
Some differ on exactly what was meant by "acceptance of emancipation," but I have noticed that the pro-Confederate sites tend to leave this plank out entirely, making it logical to assume that their story on other issues may be less than complete.