And regarding bringing up an adult. I always put the adult in a funny situation and the kids go nuts, so I have always found that to be successful.
I don't think that sounds like a good idea, since the adults are the ones who pay you and they might not like it to much if they are the subject of a joke.
Actually you can put Adults into the show very successfully. The needle thru the balloon I bring up an adult to show kids how easy magic can be. If an Adult can do it anyone can do it.
I tell the Adult that I picked them cause they appear to be a good thinker. I then tell them that they have to 'become' the needle for this trick to work.
I then have them do a little 'be the needle' dance so the trick can work. Of course it doesn't. I try it...doesn't work. I then bring up a child booyah
I also do a ventriloquit skit with five Dad's...I turn them into vent puppets. Everyone including the Adults gets a kick out of it.
So tastefully done you can use Adults in the show.