I like the letter, but we should also send the letter to 20th Century Fox. They own ANH forever. It could be addressed to All three Companies. As such:
Disney Letter:
Dear,
Disney, Lucasfilm, and 20th Century Fox…
Lucasfilm Letter:
Dear,
Lucasfilm, Disney, and 20th Century Fox…
Fox Letter:
Dear,
20th Century Fox, Lucasfilm, and Disney…
You get the idea, hope it helps.