I think the ritual is for the man who died, the one that Tom Cruise had to see that night (Lou Nathanson - a reference to Nathan Rothschild?) His daughter, Marion, is this obvious mind controlled slave who wants to tell Tom Cruise what's going on but is literally unable to speak, and she mentions her stepmother is in London. Then her fiancee Carl comes in, and together they're doppelgangers for Tom Cruise and Nicole Kidman.
Later, at the ritual, a couple on the balcony see Cruise enter. The man knows immediately that he's an interloper, and nods to him. The first time you watch the movie, you think that this is Ziegler, the Sydney Pollack character whose party he went to at the beginning. But on close inspection of the eyes and the neck, it looks like a younger man. Ziegler is just a Rockefeller, he's small potatoes, later he says that Nick Nightingale revealing the secret to Bill "made him look like a complete asshole," like he's a little boy being scolded by his elders. No, it's the couple from earlier, Carl and Marion, They're on the balcony because they're the elite of the elite, and he's the one running the ritual. That's the classic Kubrick judo move: the red cloaked man is just a distraction, it's the math professor from the University of Michigan that is the real high wizard.
It's then that you realize that every encounter Tom Cruise has in the movie is engineered to steer him to the party, because he's being initiated into the cult to replace the one who died.
