The 1974 rough draft shows signs of an additional influence on George Lucas, which I've as yet left unremarked: that of The Lord of the Rings.
General Skywalker is described as having white hair and a short silver beard, and dark eyes. In Tolkien's book (but not the film) Gandalf has dark eyes and a white beard.
There's also the matter of Leia's two young brothers, Biggs and Windy, who have an adventure of their own on Yavin when they are captured by stormtroopers. Since these two children are so young (aged seven and five), they would be very short--reminiscent of Tolkien's hobbits, particularly the duo of Frodo Baggins and Sam Gamgee.
While writing the third draft, Lucas would later toy with the idea of casting all the inhabitants of Tatooine, including Luke Skywalker and Ben Kenobi, as little people, something which he admitted was inspired by Tolkien's book.
This impulse ultimately led Lucas to make Willow--for which the early story concepts apparently featured two Nelwyns, Willow and Meegosh, as opposed to having Willow be the sole Nelwyn/hobbit on screen for most of the film.
Additionally, there's the storyline of Frodo and Sam on their journey to Mordor. At the end of The Two Towers, as Sam watches helplessly, Frodo is captured by Orcs and taken to the fortress of Cirith Ungol, from which Sam ultimately rescues him. A point omitted in the film adaptation is that, in the book, Frodo is naked when Sam finds him; Tolkien implies that the Orcs sexually abused Frodo.
Even back in the 1970s people were suggesting that Frodo and Sam were a gay couple. (Not without good reason--Tolkien modeled their storyline on that of William Morris's novel The Well at the World's End, a quest narrative featuring a heterosexual couple.)
So it's no surprise that Lucas likely took the Frodo/Sam storyline as a model for writing the climactic scenes with Annikin and Princess Leia in his 1974 rough draft. Like Frodo, Leia is stripped, sexually abused, and captured by evil Imperials; like Sam Gamgee, Annikin tracks her down and liberates her from her prison.
Of course, Tolkien's overall light/dark imagery (white for the good guys, black for the baddies) no doubt appealed to Lucas too. The influence of The Lord of the Rings would grow even stronger in Lucas's second draft, where Luke Starkiller has to carry the Kiber Crystal (a powerful Force artifact, akin to the One Ring) to his father on the faraway planet Yavin (i.e., Tolkien's Mount Doom).