the narrator says "Didn't the Ghostbusters already catch a holy ghost?"
One of the customers reappears as Mr. Omar's friend. She tells Rochelle that they already met when Rochelle sold make-up.
Chris' promises from the final election gets referenced, also the fact what Caruso did to sabotage Chris.
Greg mentions that Chris became class president, which happened in "Everybody hates elections"
the assassination scene is spoofed including the Umbrella Man