From his debates with Lincoln Douglas’ attitude was not in way more enlightened than Lincoln’s.
One difference was that Lincoln was willing to have all blacks move/be moved to another country, Liberia, Panama, somewhere in Africa.
Robert E. Lee:
“Robert E. Lee’s Opinion Regarding Slavery
This letter was written by Lee in response to a speech given by then President Pierce.
Robert E. Lee letter dated December 27, 1856:
I was much pleased the with President’s message. His views of the systematic and progressive efforts of certain people at the North to interfere with and change the domestic institutions of the South are truthfully and faithfully expressed. The consequences of their plans and purposes are also clearly set forth. These people must be aware that their object is both unlawful and foreign to them and to their duty, and that this institution, for which they are irresponsible and non-accountable, can only be changed by them through the agency of a civil and servile war. There are few, I believe, in this enlightened age, who will not acknowledge that slavery as an institution is a moral and political evil. It is idle to expatiate on its disadvantages. I think it is a greater evil to the white than to the colored race. While my feelings are strongly enlisted in behalf of the latter, my sympathies are more deeply engaged for the former. The blacks are immeasurably better off here than in Africa, morally, physically, and socially. The painful discipline they are undergoing is necessary for their further instruction as a race, and will prepare them, I hope, for better things. How long their servitude may be necessary is known and ordered by a merciful Providence. Their emancipation will sooner result from the mild and melting influences of Christianity than from the storm and tempest of fiery controversy. This influence, though slow, is sure. The doctrines and miracles of our Saviour have required nearly two thousand years to convert but a small portion of the human race, and even among Christian nations what gross errors still exist! While we see the course of the final abolition of human slavery is still onward, and give it the aid of our prayers, let us leave the progress as well as the results in the hands of Him who, chooses to work by slow influences, and with whom a thousand years are but as a single day. Although the abolitionist must know this, must know that he has neither the right not the power of operating, except by moral means; that to benefit the slave he must not excite angry feelings in the master; that, although he may not approve the mode by which Providence accomplishes its purpose, the results will be the same; and that the reason he gives for interference in matters he has no concern with, holds good for every kind of interference with our neighbor, -still, I fear he will persevere in his evil course. . . . Is it not strange that the descendants of those Pilgrim Fathers who crossed the Atlantic to preserve their own freedom have always proved the most intolerant of the spiritual liberty of others?”.
As for the others, I leave that to you to research.
Another difference is that Robert Lee was willing to put his money where his beliefs were, and actually paid passage to Liberia for some of his former slaves. Obviously Lee had no problems with the idea of the Burke's moving to Africa with their children. And considering that William Burke was able to attend a Monrovia seminary, somehing he could never have done in Virginia, and become an ordained Presbyterian minister then it's clear that in their case moving to Africa was quite a step up over slavery in Dixie.
Robert E. Lee’s Opinion Regarding Slavery
You might want to go back and really read that in detail. What, exactly, was Lee's opinion of slavery? Well, he thought it was "a greater evil to the white than to the colored race", so it's clear who he's more concerned for. He goes on to state that slavery was "necessary for their further instruction as a race...", though what more they had to learn as a race after 250 years of bondage Lee didn't say. He was of the opinion that blacks were "...immeasurably better off here than in Africa..." so obviously Lee didn't think slavery was all that bad if a life here a his property was better than freedom in Africa. And as for the institution itself, Lee believed it would end when God willed it, be it 2 years or 2,000. And most of all, the fate of slavery should be left to the Almighty and that man should do nothing to hasten it's end. Except pray. And his opinions didn't change much, because seven years later he was still saying that he considered "...the relation of master and slave, controlled by humane laws and influenced by Christianity and an enlightened public sentiment, as the best that can exist between the white and black races while intermingled as at present in this country..."
The fact of the matter is that Lee's opposition to slavery was tepid at best, and non-existent at worst.
As for the others, I leave that to you to research.
I have. Both Davis and Jackson were slave owners and believed in the institution.