The director was specific in saying George Lucas, not Lucasfilm or Disney, so it would appear that he does have the say in the matter. Why would Disney need a huge amount of convincing? It's always been George Lucas himself who has been very adamant about the issue.
A friend invited me to a special showing at the Samuel L. Goldwyn theater in Beverly Hills, which is the theater of the Academy of Motion Pictures Arts and Sciences. They were showing Rogue One and an original theatrical print of Star Wars, ie before Lucasification. The audience was very...