RL, as always I love your ideas. But I often struggle to see the feasibility of them. Hopefully with this, we get the rumored extended version of this scene on the BD.

I actually think perhaps the simplest explanation would be to just cut out Kylo killing the cultists, and just cut from the Mustafar exterior to the shots of Krennic’s ship landing at the castle (replaced by Kylo’s TIE), followed by Kylo locating the wayfinder. Of course even then you still have the technical challenge of accomplishing those VFX, but you alleviate some confusion I think as to the appearance of Mustafar (because it looks very different in TROS).