The shirt Tom's wearing to brunch at the beginning has names of characters from To Kill a Mockingbird listed on it.
There are several connections to Brooklyn 99 in the episode. Karan Soni who plays Tod the manager of the book store played a cop tasked by the Commissioner (played by the actor who plays the Hayworth father) to make a play on the Captain of the 99th Precinct. Another one is that several of the kids dress up like characters from Encanto whose main character was voiced by Stephanie Beatriz who played police officer Rosa Diaz on the show.