Talia al Ghul is not only Ras al Ghul's daughter, but in the comics she was also in love with Batman and through deception had his son Damien who is the current Robin.
Rene repeatedly refers to Quentin Lance (Paul Blackthorne) as Hoss. Paul Blackthrone played Harry Dresden in the TV adaptation of Jim Butcher's Dresden Files. One of Harry Dresden's nicknames in the books is Hoss.
When the episode first aired two days prior to the theatrical release of Lego Batman, le film (2017), it featured exclusive LEGO variants of the closing logos as part of a tie-in with the Berlanti Productions logo featuring a Batman minifigure and Greg Berlanti's father saying "Batman, move your head?" while a Green Arrow minifgure, based on his New 52 outfit, shoots at the DC logo to reveal the Warner Bros. logo. Roy Harper/Arsenal became the only Arrow character and one of the few Arrowverse characters to have a physical minifigure to be released as a giveaway at San Diego Comic Con.