As of this episode, Robert Carlyle overtook Jennifer Morrison's position as the cast member with the second largest number of appearances throughout the show.
The bookstore that Alice/Tilly takes Robin to is called Dodgson's Books. (The name is seen briefly on the door.) Charles Dodgson is the real name of Lewis Carroll, author of Alice in Wonderland.
The title card / theme used in this episode is of Mexico's Day of the Dead, also taken from Disney's Coco (2017).
Episode first aired on 4/20 (April 20th) in America, at about 14:28 into the runtime, when Tilly (Alice) and Margot (Robin) walk into the bookstore, the number on the door is also 420.