The gratuities that are paid for do not include the automatic 15% added to your bar tabs. They also do no include tips of a discretionary nature such as the pool deck stewards, who are wonderful, the maitre'd or head waiter. As for the alternate restaurants, there is a "fee" attached to eating there, which is now $8 per person. This is a gratuity for those waiters who only work in those restaurants and don't receive any other kind of tip. Those tips could come out of your shipboard account, only if you don't go over that amount with other things you purchase on board.
You will not have a room steward, but a stewardess. Crystal hires women for those jobs. Those hard working ladies will also bring your room service orders, and it's customary to give them a couple of dollars each time they bring you food.
There are two parties on board where the drinks are free. Those are the Welcome Aboard Party and the Farewell Party. If you were a Crystal Society member, that would have been a third party, but you'll only get an invitation to that one once you go on your next Crystal cruise.