Yes
Yes they can
I'm not sure but I have 12 years old daughter and she have great America season pass and she can go without an adult there.
I would think so as their are lifeguards, security and a safe place. However to be sure Google their website or call. Season passes and membership passes have extra benefits along with food passes . Where as a one day pass allows only that At time of visit your parents can ask for supervision if need be or an hourly check in see guest services or ask for supervisior.
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