DominicCobb said:
One - "wait, what? Anakin was definitely dead. There's no way Vader's telling the truth. Well I guess I'll have to turn on ROTJ and find out what happened..... hmm, I just watched ROTJ and they didn't explain it at all. I'm very confused."
My solution for these - fixing number one is simple. Show that Anakin turned into Vader! I think it should be shown in full in ROTS. But, and here is how this post is on topic, you could, if you wanted to, have a flashback to Anakin being saved and turned into Vader in ROTJ.
I would almost say have the ROTS "flashback" of anakin becoming vader happen during Empire... the "search your feelings you know it to be true" line then luke gets hit with the vision of him transforming, and doesn't want to believe it..... then both luke and the audience questions if vader is the one putting the images in his head... but ultimately can believe and be shocked that it is the truth.