"Knights of Sith" was what it originally was on GL's list, Sith knights. But he cut it from the script and put it in ROTJ later. And (for once) Emperor Helmet makes sense. He's right. No offense. Coruscant and Sith were among GL's list of unused words.
Had Abbadon. Sounds cool, but which draft was it from?. The other planets he was going to do were Utapau, Alderaan, Aquilae, and Yavin. Aquilae played an important part in the original Version 1 script.