Mormon would be perfect for a bunch of Broadway newcomers, since it's so utterly hysterical, so it's a shame you've crossed that off your list. Sister Act is very fun and palatable for lots of different types of people. Chances are, your parents have seen (and maybe enjoyed) the film, and I know I would take my entire family to see it. How to Succeed...was really boring to me, but if your family would be into the novelty of seeing Radcliffe, then maybe. Anything Goes is also a light and fun option. Another good family show is Billy Elliot. Every single member of my family adored it when we all saw it.
For a play, it sounds like you'd like the spectacle of War Horse.
"Art, in itself, is an attempt to bring order out of chaos."-Stephen Sondheim