I remember seeing someone live doing similar things to the Darren Brown show (the fake homeopathy, the fake psychic readings, drawing objects people are thinking about -etc)(sorry donnie).
It was around 15-20 years ago and cannot for the life of me remember if it was him before he was famous or not. I don't think it was tbh.
The people picked to do some of the readings were people I knew and so I'm convinced it's possible for a skilled person to do what Derren Brown does without stooges.