The name “Utapau” in ROTS goes back to the original SW, but the idea of a sinkhole city postdates the 1977 film. Perhaps most notably, it was considered as an idea for Mos Espa in TPM.
I thought the sinkhole planet was from the original film as well, although maybe I’m misremembering (ROTJ perhaps?).
Where did you learn about the hyperspace-through-shield idea in TFA coming from ROTJ?
It’s from one of the earlier drafts of the film, per Rinzler’s making of book. I’ll have to check when I get the chance which draft.
JEDIT: from the “Revised Rough Draft” 6/12/81 https://www.starwarz.com/starkiller/revenge-of-the-jedi-revised-rough-draft/
I’ve seen one book (maybe it was Kevin J Anderson’s Illustrated SW Universe) claim the sketches of a “crevasse city” were done for ROTJ, but I think that’s inaccurate; several of the drawings appear in the various Episode I art books.
Thanks for the info about the hyperspace thing!