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 of the rooms 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.