In Downtown West, the prerequisites are the same as before but as I think you have played a new game, it's possible that you missed some point:
- Corruption>=2 to unlock the other option than "kick his ass".
-Answer more questions from the paparazzi to meet the first member.
-Agree to do what he asks to have the first scene and unlock the hideout.
(To win easily corruption > Touch brent the first day and try to touch Tristan before going to sleep (in the guess room). There are other ways but these are the quickest as they happen in the main story and does not require you to follow any side story.)
I will also add a new way to unlock the gang, since I don't want the game to be punitive. I want only you to decide whether or not you want to follow one (or more) character(s).