This project is very much in your hands. As Trooperman is boss on SOTD, you have to be boss here. There are too many ways to do this and you're the one who's going to put in the hard work.
The intention, I believe, is to make an ANH that fits seamlessly into the Saga. The premise behind this notion is that Anakin's fall in Episode III puts the OT into a new context that could flow better out of Episode III with a little tweaking.
I've suggested that making Obi Wan honest with Luke will maintain a level of integrity that Obi Wan demonstrates in both the PT and the original release of ANH, but which is undermined by the "reveal" of ESB. Further, I suggest that "reveal" is undermined by the fact we all know Vader is Luke's Dad long before it is revealed to Luke.
But if we go down the road of telling Luke the truth in ANH, then we create a subtle but powerful difference in the story of Episodes IV-VI. Luke becomes a man with a secret, a dark heritage that he comes to deal with.
When he is told the truth in episode IV, he doesn't and cannot understand the full impact of it. He doesn't know who Vader is. He never once, in the original cut, acknowledges any recognition of Vader. The audience knows, but Luke does not. Even if you tell Luke that "Your father became Darth Vader" -- he still doesn't know what it means until he's gotten off the foresaken deserts of Tatooine and seen what it's really like in the Imperial controlled Galaxy. This barely has a chance to happen in ANH -- he sees Mos Eisley, The Death Star, the Rebel Base -- and that's it. He never meets Vader or has the man pointed out to him by name. He sees a big guy in black cut down Obi Wan, but does Luke know that man's name? There's no indication of it and no easy way to fit one in. I believe, at the end of ANH, unless we add it -- Luke does not know who Vader is. "Vader's my father, but who is Vader?" might sum up his position in the end.
An idea that will bring this movie home, then, would be to have Luke recognize Vader on the Death Star as the man in black who kills Obi Wan. Thus, his stunned reaction to Ben's death does double duty as the realization that he just saw his own father -- an evil man who murdered his mentor. His reactions through the rest of the movie should become more muted and somber, as this is a heavy thing to bear. If we can reinsert the reference that a pilot makes to Luke's father before flying off to Yavin -- this will have power to it. Then, ultimately, in battle -- Luke uses the Force and defeats these doubts and fears that have risen in him. He doesn't know Vader's on his tail. Vader doesn't know he's hunting his own son -- but the moment Luke trusts the Force he transcends these worries.
I believe that this movie thus becomes the story of a boy who finds out he has a dark heritage. But bravery and guidance from a friend help him escape that inheritance as he embraces the Force and becomes a hero.
I think that takes better advantage of "the story so far" -- giving us an Episode IV that grows out of Episode III more organically. But Jeebus help us, the changes can't stop there...
In Episode V, Vader is personally looking for Luke. Presumably, the man who destroyed the Death Star became a celebrity of sorts. Vader recognized the power of the Force in this pilot and the name "Skywalker" cinched the deal -- this had to be his son. Luke, meanwhile, has certainly learned who Darth Vader is -- but recognizes the need for training. With the knowledge that Vader is his father, he carries the burden of this heritage through his training. He knows he is preparing to do battle with the forces of the Empire. Chiefly, this must mean his own father -- at least to him. Receiveing visions of his friends in trouble -- he cannot stop himself and rushes off unprepared to save them and face Vader. His brashness costs him dearly -- especially when he discovers Vader knows of him and wants him to take a place at his evil side.
In Episode VI, Luke has escaped his brash encounter with his father. That experience has wisened him. He senses his true weapon against Vader is the good that still exists inside the villain. He chooses this path and heads into the final conflict with this in mind.
That is quite a bit different than what is there. To my mind, it plays a lot smoother as the redeeming of the chosen one. It doesn't seem so fast and loose when it comes to the material point: how is Vader to be redeemed?
Aside from all the aesthetic changes that could tweak the OT into a better match with the PT -- are we really on board for all these story changes that would come from changing the "Ben's Hut" scene?
I can say that "I am if you are." If you aren't, then we should set it aside. I will do this edit some day if we don't do it now. The rest of our changes here will make such an edit much easier.
More later.