I believe Telecine was the first to remove a deleted scene time code, specifically the ‘Kylo Searches the Falcon’ deleted scene. He did a pretty good job, and I believe Sir Ridley has mentioned having a go at it as well for his own edit (correct me if I’m wrong).

I think Sir Ridley and Neverar also collabed on fixing/color grading the ‘Leia and the Resistance’ deleted scene as well as a bit of the Jakku Message scene, but the dialogue was modified to serve the Restructured edit. That’s all of the TFA deleted scenes I believe.

I can’t personally speak on what is possible or impractical, but if you don’t mind me interjecting, I would also consider which of these scenes are really worth the trouble.

I definitely think Ridley having a go at the Kylo/Falcon scene would be a nice addition to the film and doable. And you pointed out some details with some of the TLJ deleted scenes that I hadn’t noticed. I think fixing little errors in the jacket scene, BB8 message scene, the caretaker village sequence, and certain moments of the Supremecy Incursion might be worth the trouble for some. I’m not sure many of the unfinished scenes would be worth the effort, but maybe shots could be scavenged from them.

Regardless, I really like the idea of making a database of usable deleted scenes overtime as people edit them.