here are my suggestions/answers ...
Do another post titled "Caribbean Princess Patters?" and then ask if anyone taking the cruise before you would be willing to keep theirs and mail them to you or make copies and mail them to you. For this to work, you should offer pay postage. It worked for me.
As far as tipping in concerned ... yes you can have the $10 removed from your account. I don't think this can be done at check in, but you can certainly do it at the Purser's Desk once on board. If you prefer to give the people cash you can do that instead (at your own descretion).
About the movies under the stars ... the Princess web site says they show G, PG, and PG-13 movies. You just need to watch the Patters to see what is playing when. They have full details on their site at www.princess.com
Formal nights ... As a child my parents always took my brothers, sisters, and me to the formal dinning. Like the previous person said, it's great experience for a child to learn how to behave in that kind of setting without anyone being too critical. Most people will be dressed up, but it will still be an easy-going atmosphere. They don't have to dress up too much if they don't want to. Church clothes will suffice.
I know your entire family will have a ball. Just remember it's your vacation and as long as you are respectful of the other people onboard, it will be a very memorable one.