Hi Kelly,
I was reading one of the recent Kids Club Navigators on Barb's site, and it showed pictures of each counselor on it. It looks like there are about 11- 12 counselors per group in that navigator. So it seems that over the course of the trip, any of those 11-12 might be interacting with your child.
Regarding tipping, I know some people have tipped all 11+/- counselors in the past, and I know others who have only tipped the 2 or 3 that your child knows by name or that has interacted with your child the most based on your kids discussions, or things that you have observed.
Tipping is very personal, do what you feel most comfortable with.
- David