I think the audio change for Vader should only be applied for the Erso section (and thinking about it, there might be a way of removing the reference to Galen without using other Vader audio sources). The pun isn’t great but is what it is (as a Prequel film, it doesn’t really destract with the “No!!!” of his previous appearance).
Original: “I expect you not to rest until you can assure the Emperor that Galen Erso has not compromised this weapon in any way.”
Edit version: “I expect you not to rest until you can assure the Emperor this weapon has not been compromised in any way.”
Don’t know if that would be possible though.
This is definitely possible - I’ve tried that too. Again, just needs some skill and fine-tuning, but i did this test to see if it could work…