I’m wondering how the heck you have the time and inclination to ever look at a passenger manifest unless someone else was to inform you of some dodgy geezer. Then what? Past history is no guarantee that his bad behaviour being repeated as well all make mistakes and learn from them.
i think you got involved in something beyond your pay grade and concern. A phone call to Ops voicing your concern may have been the route to go.
Anyway, since he couldn’t make any rumpus it seems you did the right thing haha! Good luck in your chat with tea but no biscuits. Wouldn’t it be wonderful if said character forces a diversion on his next flight? Good luck.