In the dance scene with the strobe light and tv. at first you can see that the dancer is wearing leggings under the suit, then she's not, then she is! Speaking as someone from the Pittsburgh area, the director made excellent use of location. especially Mt. Washington area and the local celebrity traffic cop.
In the scene where Alex is auditioning, a double replaced her dancing, which looks nothing like her. The double is very masculine and muscled with a jheri-curl wig.
-Blackman kidly wrote in to add that the double is Richard Colon aka Crazy Legs of the Rock Steady Crew and he did the backspin because he couldn't teach Alex to do it in a day.