Depends on your type of membership
I received 4 passes with my membership but they are one time use passes
You get 2 guest passes with any level above solo, other levels allow more dependants (family members) see the zoo website for more info.
Yes, there are different kinds of memberships with a different amount of people you can bring depending on the price of the membership.
I think you have to buy guest pass. You can ask their onsite staff or check their website.
Thanks! Your answer is awaiting moderation.