For the most part what you're saying is pretty accurate, A lot of people look at Lincoln as a die-hard abolitionist that wanted to become president specifically to free the slaves, it's simply not true. The thing about Lincoln's quotes about ambivalence towards slavery could simply have been an appeal to moderacy at the time, it's hard to really know with politicians. I think back to Barack Obama's original stance on gay marriage, and how David axelrod said that he was faking that stance in order to appeal to moderate voters. This is a very common maneuver for politicians that are seeking radical change. Ie appear to be more moderate than you actually are.