In the 1989 movie of Batman with Jack Nicholson as Joker, what happened to his remaining henchmen after he fell to his death from the bell tower?
We don't know for sure but they were possibly rounded up, or escaped to the criminal underworld
The last time they're mentioned in the script, they're deserting Joker at the parade, before the police have appeared.
INT. BATWING COCKPIT - THAT MOMENT
Batman clears trigger safety mechanisms and presses switches to arm the rockets and laser. He sets the missile sights.
AERIAL SHOT OF BATWING - THAT MOMENT
The Batwing, with all its weapons primed, descends.
EXT. BROAD AVENUE - THAT MOMENT
Goons glance at each other and begin to run away.
The Joker stares at the retreating Goons in disbelief.
JOKER: It's just cookin' good, you SCHMOES! What's going ON?
Deserted by Goons, he looks up at Batwing. Batwing's spotlights come on as it speeds towards him. Joker LAUGHS, steps into the middle of the Avenue, and opens his arms.
Soon after, Gordon arrives:
The crowd is pressing in on Joker. Gordon ARRIVES with SMALL POLICE FORCE. Joker pulls out another GUN and FIRES in the air. He backs off quickly down the street.
The police force may have been able to apprehend the goons, but it isn't mentioned in the script.
We know the goons are terrified of both Batman and the Joker, so they probably left the entire situation as fast as they could.
While they're not depicted as the smartest, such as when one suggests they check Batman's wallet, given that they're free on the streets, it seems likely that they're capable enough to flee the police when they need to.