This is Susan Hogan's (Miss Hochschild) second connection to the Arrowverse. She has portrayed Nate Heywood/Steel's mother in DC's DC's Legends of Tomorrow (2016).
Betty Buckley, who voices the owl in Nia's dream, played Samantha Arias' mother Patricia in season 3 and, along with Odette Annable as Sam, returned for season 5's "It's a Super Life (2020)", the milestone 100th episode.
When she tasks Kara, Nia, and William with getting an interview with one of the Super Friends, Andrea orders them to do whatever it takes, and suggests shining a big "S" into the sky, an allusion to Batman and the Bat-Signal. Kara's response about Supergirl being too busy to do a "celebrity puff-piece" is a direct quote of a conversation between Bruce Wayne and Clark Kent about the Daily Planet's propensity to publicize every time the Boy Scout pulls a cat from a tree.
The names of the characters "Joey" and "Orlando" are an homage to longtime DC writer and artist Joe Orlando.
Joey is reading a "Captain Carrot" comic book when Kelly first meets him. This was a funny animal superhero comic published by DC in the 1980s. "In-Universe", Captain Carrot is actually a multi-versal variant of Superman, with commensurate powers.