The Wayne Mansion cut was filmed at Casa Loma (Toronto Canada), same location for several movies including X-Men.
When asked by Dick if the FBI knows about her, Kori says "she avoids the guys in the basement." This is a reference to the X-Files, as Fox Mulder's office was in the basement of the FBI.
When Jason Todd tells Dick about the pictures the Joker texted, this is a reference to The Killing Joke, where The Joker captures Barbara and tortures her, sending her pictures to Commissioner Gordon.
Triagon (Seamus Dever) pretends to be a police captain. Dever previously portrayed Det. Kevin Ryan in Castle.