The first glimpse you see of the Halloween party, you see a tray with champagne glasses. Boris the Warlock walks to it and picks one up. A few minutes later, Boris arrives at the front door of the house with his familiar, Eva, and greeted by Endora.
Halloween guests constantly change positions or partners.
Even though the Kravitzes live across the street from 1164 Morning Glory Circle, their address is 1168. Even numbers are typically on the same side of the street.
Although the character Eva is a female, the cat that is brought to the door is clearly male.
Willie Mays indicates that he has to leave in order to get to the stadium for a game--even though it's a Halloween party and the Giants' season would be over, not making it into the playoffs that year.