As we know, Zuul, the Gatekeeper, is one of the minions of Gozer. Zuul seems to be a unique entity, the counterpart of Vinz Clortho, the Keymaster. That is, Zuul appears to be a name. However, Vinz Clortho also says that many Shubs and Zuuls were roasted by Gozer when he took the form of the Sloar. I found a site with what appears to be the shooting script, and the spelling of the two is the same.
Is this just a coincidence, or is there some connection between the two? For instance, is Zuul not Zuul, but just a Zuul that happens to serve Gozer?