Hello SD Cruiser;
I would agree with Chef Ken; you say you have a multi-generational group and I would say that Princess probably has the broadest appeal. I wouldn't think even HAL would have a drastically older crowd on a 7 day Mexican Riviera cruise; but I think Princess would be better suited to a wide-ranging group. And from my observation, I would say they have fine childrens' programs.
But also as Ken says, you will have a great time which ever way you go.