Hercules is one of my all time favorites, I watched it sooo many times as a kid and sang along as Meg/the muses/everyone. But, I don't think it would do too well on the stage, and I'd hate for it to ruin such a brilliant thing as the movie.
I've been trying to think of someone to be for Halloween- I haven't yet been a Broadway character although 2 years ago I was Wednesday Addams and that was by far one of my best.
I'm 13 and I understood Sweeney completely when I saw it- and I had not understood it at ALL before that. But on the other hand, I don't think your son would enjoy it very much (although he would get the gist of the story) unless he's listened to the cast recording before- so it'd probably be a good idea to stay away from Sweeney.
At Sweeney Yesterday: Woman #1: Do you think they're actually playing the instruments? I'm pretty sure there's an underground orchestra. Woman #2: Yeah. That sounds about right.
They aren't even consistent with their bad spelling. Under Elena it says Charlotta, under Joan Sobel it says Carolotta, and under Danielle they finally got it right.