Lincoln wouldn't get the black vote as long as he had an R next to his name.
I'd vote for Jefferson. I'm not sure who would win.
Lincoln might get the black vote, because he's 'the great emancipator' and Jefferson had the whole slave owning issue. Hard to say.
Jefferson would get the NRA endorsement. So the pro-gun crowd would go for him. The anti-gun crowd would take Lincoln unless he took a pro-gun stance too.
Then there's the whole fame thing - each of them has big name recognition, but who in history is looked upon more favorably? Lincoln might have some of his Civil War actions brought up in ads, so that could be a detriment to him, but he is still very well loved.