K.C.
I can't answer all of your questions, but hopefully some of this info will help. I sang at Carnegie Hall with my choir when I was a senior too, so I can promise you that you and your family are in for a treat!
You do not want your own car in NYC. Parking is hard to find and ridiculously expensive. Plus, many places are walkable or easily accessible by subway. You'll be SO much happier if you don't have your own car to deal with. A cab from the airport is, I think $40 flat fee to anywhere in Manhattan, plus tip. Or, if you fly to Newark, NJ airport, it's easy to take the train or bus to the city instead.
Statue of Liberty & Ellis Island are the same place and they are not too far from Ground Zero. Plan to do those at the same time, since they aren't too close to the other things you mentioned above.
For a Broadway show, you can get discounted tickets at the TKTS booth in Times Square. You can walk from Times Square to Broadway and to Carnegie Hall pretty easily. You can walk to the Empire State Building and Central Park from these places too. They're also near Radio City Music Hall. Midtown is not that spread out and you can easily walk around to see all of these different places. You can window shop at the fancy 5th Avenue stores too.
Jerry's Deli... do you mean the chain restaurant? NYC has several famous delis in the midtown area (and other parts of the city). Ask around for recommendations, since Jerry's probably isn't your best bet (but I'm blanking on the names of the others right now)
Expect to pay upwards of $200 per day for a hotel room and even more than that if you want a suite.
I know you don't want to have to look a lot of things up, but I do recommend getting some sort of guidebook with good maps inside, since it sounds like you really don't know the layout of the city. It'll save you a lot of time and prevent you from getting lost.