chamaleon guy is dead because he got fucked up during the fight at the bowling alley.
he gave BJ the gun, BJ realized he didnt really want to kill ichiri and shot the boss.
the way its shown we are meant to interpret that, everyone in the mafia is looking at the dying boss, BJ would now be the new boss.
but the oddly unclear way these events are presented makes me doubt this is all real basically. seems like a set up for a twist.