I have a question if we take a cab to atlantis can we go to the pool and slide etc or are they gonna figure out were not hotel memebers?

They will know you are not a guest, but you can purchase a guest pas for $25 and do everything there.

I heard that does not include pool and slides just the tour and casino

The $25 dollars covers The Dig ( aquarium), and walking around the grounds....You can also use their grounds to get the beach ( easy access).
The quests of the Atlantis have special wrist bands, special towels, and canopies to flag their lawn chairs. ( we didn't know this. We snagged a couple of lawn chairs on the beach. No one kicked us off the chairs, but we did get some dirty looks.) I thought the Atlantis was beautiful, but I liked Paradise beach best. Next time, I'll go straight to the beach , and skip the Atlantis...Some people on our cruise went snorkeling, and had a fabulous time....