Back from the Dead: When BoJack hears about Ethan Around, he feels that he should be involved in some way, and suggests several ways to write around the fact that The Horse died at the end of Horsin' Around
Earlier In the episode when the brothers first meet, Captain Peanut says "what is this? A flashback episode?"
The Bus Came Back: Laura, Princess Carolyn's assistant from season one, returns and serves as a plot point. Her beefed-up role appears to be in connection with her voice-actor, Rachel Bloom, suddenly becoming a Golden-Globe winning actress in Crazy Ex-Girlfriend.
Downer Ending: Princess Carolyn ends up losing all of the parts, costing BoJack his chance to reconnect with Kelsey in the process.
Furry Reminder: Captain Peanutbutter's nose is pinkish instead of brown, a subtle foreshadowing that he's sick.
Political Correctness Gone Mad: When Diane first meets her nephews, she tells their father how cute they are... then hastily backtracks and says she doesn't make any assumptions about their personalities based on their appearances.
Spin-Offspring: Ethan is interested in creating one of these for Horsin' Around called Ethan Around, focusing on Ethan adopting 3 horse children.
Truth in Television: Captain Peanutbutter reveals to his brother that he has to get surgery for a twisted spleen, a very common condition for golden retrievers.
Visual Pun: The Labrador Peninsula is actually Labrador, Canada, with its shape altered to look more like a Labrador's head.