According to the ROTJ novelization, The Emperor knew of Yoda (although he had to reach far back into his memory to recall the little green Jedi Master), however Darth Vader/Anakin Skywalker had no knowledge of Yoda and even, if I remember correctly, expressed to Luke in his unmasking that he wishes he would have met the ancient Jedi.

According to the same novelization, Owen Lars was Obi-Wan's brother, so says Obi-Wan himself to Luke on Dagobah. Personally, I think this is kind of sketchy since Owen and Beru seem to speak of Luke's Father as actually being Owen's brother and Owen actually being Luke's brother and Owen speaks of Obi-Wan as an outsider who took Anakin out on a damn fool idealistic crusade. Weird. Furthermore, it's unclear whether or not both Anakin and Obi-Wan were supposed to be Owen's brothers, thus making them siblings and Obi Wan...Luke's Uncle! :0

Additionally, The ESB working script explained Vader's injuries and the necessity for his life-preserving armor due to falling in a nuclear reactor rather than falling into a molten pit of lava like Lucas himself stated in 1978 and what the ROTJ Novelization and Lucas's own Prequels agree with. I guess you could assume that Vader's unmasked and bald head is a result of the radiation/cancer from falling in the reactor rather than falling into the pit, and also it seems like his obvious respiratory problems may be present because of lung cancer or something effecting the same issues.

This is a stretch, but I believe that the X-Wings were supposed to have been the main starfighters of the Old Republic used during the Clone Wars and were VERY out of date in comparison to the recent TIE Fighters.

Then there was the whole O.B. 1 (Obi-Wan was a Clone!) Theory....creepy!