In the climactic brawl, just before Matt's final confrontation against Negaal, a casino dealer, played by stunt performer June Castro, comes out of nowhere to help dispatch Negaal's men. She is nowhere to be found in the rest of the film so it is unclear what her involvement in the film is.
When Chalky is asking Matt if he would like to send his condolences to David Sloan's family, it must be towards his extended family which might include Xian Chow, Jack, Janelle, Marcos, Isabella, Casey Ford, Lando Smith, Megan Laurence and his wife Vicky. Obvious reason is because David's parents and brothers Kurt and Eric are dead.