This idea has actually been discussed before. Since Anakin is shrouded in his robes, this is something that could possibly be reshot if some plates were created and then actors in costume films in front of a green screen. You would also need to rework some character dialogue to remove mention of the Separatists on Mustafar, and possibly add some to get that info across.
And you could just trim Obi-Wan’s Utupau mission to have Obi-Wan jump down before the Separatist leaders leave. That way we could just assume they get captured by the Clone Army before they can escape.
I have to say I’m not that surprised this has been discussed before because ever since I re-worked it like that in my headcannon, it seems to be so obvious that this is what should have happened. Why did George Lucas decided to make Anakin’s “badass” scene with the separatists?! Most people don’t care about them, we want to see Anakin destroy some Jedi! It would have made so much sense, especially with the cuts back and forth with Palpatine declaring the Jedi enemies of the Republic and creating the Empire.
Instead of reshooting the scene, could it possible to just digitally add some lightsabers to the separatists, and maybe digitally insert some different faces to them?