How does membership work? For a 4 person membership, is everyone's name on the membership? Can parents take the two kids, or grandparents take the kids too?

You buy your membership for 3-8 people. Adults are named on the card, and must present ID when they get there. They can take as many guests as there membership allows for. I had a family 6 membership and used to take my 2 kids, my friend and her 2 kids. If you want grandparents to be able to go without you, make sure you add them as named members.

Call on that info.

Not sure. But probably worth every penny.

Unfortunately I don't know how the membership works. You would have to call or go online and find out.