You are right. The dialogue from Star Wars (and Return of the Jedi) suggests that Luke's father/Anakin and Ben/Obi were equals rather than master-apprentice. However, with the ret-con/merger of the characters of "Anakin" and Vader you then kind of have to accept that Luke's father was Obi's apprentice. But, then again, this is 1979, here, before all that and back when they weren't one and the same.

Still, though, at the end of this comic, the creature states that Luke is wearing the lightsaber of the Jedi who was chiefly responsible for saving them and Luke says that his father was someone he could be proud of (this line is all the more poignant with the character-meld/retcon in my mind!). Furthermore, this Vanilla Ice/Muffin Hair man with Vader and Obi-Wan Kenobi most likely wouldn't simply be some random pupil since his presence is kind of odd and, seemingly, at equal status with Kenobi and Vader.

In conclusion, it is my opinion that the man with the bad hairdo is none other than Marvel's interpretation of the visage of the father of Luke Skywalker, only placed anonymously in one panel to avoid attracting the attention of our boy George.

In fact...I doubt George has ever seen this panel! Boy would he probably be ticked! Heck, he would probably want to have the next Dark Horse compilation/omnibus of the Marvel comics have Hayden's visage tacked on to this panel! :P