John Doom said:
About that "felt familiar", my guess is that Luke had a vision of Dagobah (like later with Cloud City), but he doesn't remember it anymore as usually happens with dreams.
That's all I've ever thought it was. Start spending too much time trying to assign deep meaning to anything from Lucas and you end up realizing he was a weak writer and story teller. His quality work is when he's collaborated with people who are talented: Marcia, Kurtz, Spielberg, Kasdan, Ford, etc.
He wrote, filmed, and released the "no, there is another" scene without giving any thought to where it would go or who 'the other' actually was. As has been proven in countless interviews with people who worked closely with him, Lucas doesn't think much beyond the moment or the surface. Fix it on the fly later (poorly).