I think there is a small crew there.
With the wait staff working multiple venues - which you may already be used to.
As for pay - I think you may mean tip. Yes they can do this in advance on a ship account or pay at the end of the trip.
I do think there may not be enough crew to go around and you may have to go through a contract to get to work in one of the specialty resturants.
No reason to cancel tip if service is good. Keep smiling - learn to communicate well in English.