How do you think Luke got his X-Wing back? He left it there on Cloud City. Did he go back and fight the Emperials who had taken over the city to get his craft back? Or was that a new X-Wing we saw in ROTJ.
My theory, is that the Emperials left the city after Landa high tailed it out of there and Luke got dropped off by Leia so he could pick up his fighter.
And I have never had a problem with the whole Luke/Leia love triangle. It makes perfect sense to me. Who cares if Lucas didn't plan it from the beginning. The plot line works. Role with it baby.