When Holt summons Cheddar the Corgi the song playing as he runs in is 'I Wanna Be Your Dog' by The Stooges.
They obviously jumped the show ahead a few months so that Amy could match Melissa Fumero, who was pregnant, with how far along her character Amy was in her pregnancy.
Amy is wearing a bulky Halloween costume in the scenes set six months prior to conceal the fact that Melissa Fumero was already visibly pregnant at a time when her character was not.
The title of the episode combines the name of three holidays: 1. Valentine's day (the first two letters), 2. Halloween (the next 4 letters) and 3. Easter (the last part of the title).
The discount Infinity Gauntlet that Jake uses for the heist trophy is called the Infinitude Gobbler, from the (fictional) movie, Avengaboys. This is probably a reference to the Dutch Eurodance music group, the Vengaboys, who were popular in the '90s with songs such as 'We Like to Party'.