nhoj3, solid analysis. I’m sure many others have broken down the plan in a similar way. I also came to a similar conclusion when I first started thinking about fanediting ROTJ. After some time I tried to think of a simpler solution that would require less changes, since even this multiple back-up plan theory stills seems overly complicated. But after some time, I think that maybe Luke’s plan was to get to the Sarlacc all along, and to get as much back-up there for the escape as possible.

How does this work? It works under the assumption that Lando has learned the ins-and-outs of Jabba’s palace since he has been undercover. Maybe Lando came to the conclusion that escaping the palace was almost impossible, and Jabba would be unwilling to bargain. Jabba himself is practically untouchable, but one of the few times Jabba leaves his palace with only a fraction of his guards is when he goes to the Pit of Carkoon for executions. So, instead of someone having to escape the heavily fortified palace, Jabba literally takes prisoners out of his fortress and practically hands them a getaway vehicle (the skiffs).

With this in mind, things can start to make more sense. Luke “gifted” the droids to Jabba in order to get them conveniently placed jobs that get them on the inside (maybe Lando sabotaged the previous barge droid and translator). Chewbacca was brought in as extra muscle for the sail barge escape and as a means for Leia to get in. Leia’s mission was to get Han out of the carbonite, but she went in knowing that actual escape was unlikely. I don’t think they planned for Leia to be made into a slave girl, but Leia did make it work in the end. Bottomline, Han had to be let out, otherwise he would be left frozen in the palace while everyone else went to the Sarlacc to be killed.

And if you think about it, Lando could have let Han out himself, but actually getting out of the palace was pretty much impossible, and they needed as much back-up as possible for the sail barge escape, which I think was why Leia and Chewie were brought into it. And with Lando compromised, they wouldn’t have anyone on the inside to make sure that all the pieces were where they needed to be.

Then it comes down to Luke. Luke’s job would be to take out the Rancor, the only other man-eating creature keeping them from the Sarlacc (and their escape). I think Lando obviously would have told Luke about the trap floor, which makes me think falling into the Rancor Pit was intentional. Once that inital means of execution was out of the way, the only thing left to satisfy Jabba’s well-known ego was to kill his enemies with the Sarlacc. Everything points to it; R2, Chewie and Luke seem confident the whole time, R2 is exactly where he needs to be with the lightsaber, and everybody is nodding their heads at each other like this is exactly where they wanted to be. Maybe they just didn’t tell 3PO so they could add an air of authenticity to the situation. They can’t all be cool, calm and collected.

And I think there would only need to be minimal changes to help this plan be clearer.

I would rather remove as little footage as possible, but when Luke is in the Rancor Pit, you could cut a shot or two of him desperately trying to get out through the door. If he needs to kill the Rancor, he shouldn’t be trying to escape just yet. So show him running across the pit, cut to the Rancor turning around, then cut back to Luke looking for the gate switch.
Another change that could help would be to add/alter a line from Jabba. For example, when Leia and Han get caught by Jabba, he says something before Han starts trying to talk his way out of it (like he always does, EVERY TIME), but there are no subtitles there. Maybe Jabba could say something about how escaping his palace is impossible, or how they never would have gotten past all of his guards, or how no one leaves his palace unless he allows it, etc. There may be a better place to put this kind of line, but a line like this could help foreshadow or hint to the plan.
A third, not completely necessary change would be to add more guards throughout his palace.

Personally, I’ve accepted this as their plan and I think the movie already works pretty well as is with that in mind. The main thing that sticks out to me is Luke trying to get out of the Rancor Pit, but one could probably rationalize that somehow. These changes might help make that plan clearer if Adywan or another editor felt the need to clarify the plan.

Sorry for the long post, just thought I would put this idea out there while it was on topic.

TL;DR The Han Rescue Plan was to get to the Sarlacc Pit. It was the easiest way to get everyone out of the palace, away from the majority of Jabba’s guards, and to get a free escape vehicle.