Random thought I had a while ago.

What if the exposition in ROTJ could reveal that luke has been missing since the end of ESB. So he recuperates with the fleet and then just disappears?

The material would be a bit thin on the ground, but perhaps his reveal could be within the sarlaac scene, so Han is about to be fed by himself? Luke could be on the barge and is revealed then.

I agree with Mithrandir about the current state of ROTJ. Jabba's palace feels like a huge intermission really. It made sense for a trilogy finale, but not for a saga finale.

I would suggest making Jabba's palace have more of a hook in the prequels, then it may just have some relevance to tying up some loose plot strings. Dealing with some long unfinished business.