Depending of course what your definition of the word 'is' is
President Bill Clinton said something close to this while trying to explain that he had not lied when he denied having sexual relations with Monica Lewinsky: "It depends upon what the meaning of the word 'is' is..."
You can hear it here.
the kid in the teen horror movie who turns out to be possessed
A likely candidate for which teen horror film Pynchon is referencing here is Night of the Demons (1988) (aka Halloween Party). Wikipedia
Joke on the ole pat-on-the-ass mixed with "pater familias," explained below.
The pater familias, also written as paterfamilias (plural patres familias), was the head of a Roman family. The paterfamilias was the oldest living male in a household, he had complete control of all family members until he died. Once the paterfamilias died the next oldest male would then have control. The term is Latin for "father of the family" or the "owner of the family estate". The form is archaic in Latin, preserving the old genitive ending in -ās (see Latin declension), whereas in classical Latin the normal genitive ending was -ae. The pater familias was always a Roman citizen. From WIKI.
RPGs are Role-Playing Games
Ms. Cheung's bleak announcement about real life and make-believe
So what's the reference here? Who's "Ms. Cheung"? I suspect it may be a misspelling of newsperson Connie Chung's name? She was in NYC at the time of the 11 September attacks and covered it for CBS News, focusing on Cantor Fitzgerald, the Manhattan bond-and-equity-trading firm that was obliterated by the 9/11 attacks. But I can't find anything of her talking about "real life and make-believe"...
Goombas, known in Japan as Kuribo ("Chestnut People"), are a fictional species of sentient mushrooms from Nintendo's Mario franchise. Their appearance is based on shiitake mushrooms. Wikipedia
Granada Asbury Park Uncertainty Question
From the lyrics of "At Long Last Love" (written by Cole Porter, popularized by Frank Sinatra)
Is it for all time or simply a lark?
Is it Granada I see or only Asbury Park?
From this page: a term used to describe a scented trail left by the fragrance wearer.
a.k.a., Microsoft headquarters
racks of electronic gear receding into infinity
Describing the Bleeding Edge front and back cover photograph. On the next page, Eric speaks of "Bleeding-edge developments"...
Bleeding-edge development phase
On the previous page, Pynchon describes a server farm that matches the Bleeding Edge cover photo.