Since Batman and Jim Gordon are going to be background characters and more representational than actual, I figured Batgirl could use some Gotham PD friends. Two people who understand what it's like to try and prove yourself.
Renee Montoya the daughter of a private eye is constantly trying to both prove herself as lead detective of the Major Crimes Squad as well as solve her father's 15 year old murder case. Renee was only 12 when her father was killed. He was a great PI and a hero to her. She doesn't know the case he was working on or have any leads. The only thing she knows is that she stopped to look at a flower cart and when she looked up her dad walked past an alleyway and a gun stuck out of it and shot him down. The investigation eventually went cold, and the then corrupt Gotham PD didn't give her any hope that the case would ever re-open. So she worked hard when she got of age, and soon after she graduated and became a junior detective. Within a short time of dealing with other cops giving her a hard time because of her age and gender, she overcame it all and because head detective of the major cases.
She's tough as nails and has a noir flair to her style of investigation. I gave her the fedora both as an homage to her dead P.I. father as well as a nod to her future as The Question. I'm also keeping the idea that she's a lesbian from the comics. Her transition from background character to foreground hero and lesbian was handled really well I think for comics and I think it would be a slap in the face to her fans to say otherwise. Also I think her link with the Kathy Kane Batwoman in the comics makes her an easy transition to ally of Batgirl.
Harvey Bullock is always a fat slob, but honest cop. These are two things I felt like twisting around. While he's still an honest cop he's actually a former heavyweight underground boxer. While he never got a break into professional boxing, he was known in the fighting circles to be one of the best. That is until he broke his shoulder. It healed but no one believed in him ever again. He fell into a slump and as one does in the underworld when you're down and out, you make bad decisions. His bad decision came with white skin and a terrifying laugh. Harvey became one of the man painted up faceless thugs to back Joker. Albeit for a brief time. All was fun and games until the first time Joker hurt someone for no reason in front of Harvey. Batman had just come in and saved the day as always but Joker in a nasty bid tried to kill a civilian hostage. He gained the upper hand while batman tried to help the hostage and Harvey quickly turned sides. He beat the Joker bare knuckle until he was unconscious, saving Batman's life. Batman repaid the thug by talking with Jim Gordon about not arresting him. He believed in Harvey when he said he could go straight and would never go back. He cleaned up his act and thankfully avoided getting a conviction on his record. He then entered the Gotham PD academy and after graduation he moved through the ranks eventually landing himself a Gold Badge and working under Jim Gordon specifically. Only Jim and Batman know of Harvey's costumed hood past and their silence has been repaid with one of the hardest working and toughest honest cops out there.