I am really liking the premise of this game, particularly the setting. The setting makes it a little different from the other games about gangs and mafia that I’ve seen. So, I’ve would be very interested if you could find some way to deeply intertwine this aspect into the game.
On the subject of personality traits, I think preset backgrounds could work. However, you might need to elaborate on the weaknesses and strengths of the backgrounds. I think Vendetta did something similar too. This is especially so if you are planning to have more than 3 stats. (It might make it more complicated) But, I have seen it work both ways. So, I am fine either way.