Captain Tim can be seen sleeping when Peepers barges into Hater's bedroom.
According to Frank Angones' Tumblr, the forest planet Westley encounters Wander and Sylvia at is named "Bestley V".
The song Wander sings in the final scene is "Wander Over Yonder End Title Theme", which was originally going to be the theme song in the show's original pitch.
Not only is Westley the smallest of the Watchdogs, he's also the only Watchdog to wear a two-piece suit.
Prior to the final scene where Wander sings "Wander Over Yonder End Title Theme", an instrumental version of said song can be heard at a few points. A relaxing ballad version is heard during the scenes where Westley is realizing Wander and Sylvia are not as bad as he thought, and as Wander's banjo music when he and Sylvia are first seen and during the dinner scene in the cave.