Haley's Circus, where the Buthcer of Gotham was a knife thrower, is also the circus where the Flying Graysons performed in regular Batman continuity. It's also where Dick Grayson watched his parents fall from the trapeze, while Bruce Wayne was in the audience.
A reference is made to The Iceberg Lounge, a nightclub owned by Batman villain, The Penguin.
Robinson Park is probably a reference to American comic book artist Jerry Robinson, who worked on Batman comics in the 1940s. He is credited with co-creating both Robin and The Joker.