Can kids or adults wear what ever or does it have to be actual swim suits?

You need a swimsuit to swim. Otheriwse, you can wear whatever to lounge.

If you plan on just lounging you're good to wear whatever I haven't seen them enforce any dress code

I saw people wearing like board shorts and a shirt but for the most part swim suits. You can wear water shoes on the beach and lazy river but not down the slides.