Yes, that was George Lucas, AND his daughter , standing on the left hand side of the screen in that scene, in shadow.
They had blue skin, but it was still unmistakeably George Lucas, right down to his beard.
That was indeed Jett Lucas as Zett Jukassa . Cool scene, and he got to use a lightsabre , George spoils his children. LOL
Jett has grown a lot since Attack of the Clones, where he had a small scene at the Hall of Records when he came to request for something from the librarian . He was 9 years old then. He's 12 now.
I could not find the THX 1138 reference, although I think I spotted it on one of the canons in one scene, the canon which ejected the spent cartridges from its rear. It was the second canon further from the camera .... not too sure though.....