Atlantis privileges? Full access to the beach, pools, water slides, and aquariums. Plus, you can sign for your food/drink and have it charged to your guestroom account at the Comfort Suites.
Can you do this all in one day? You do realize this is a vacation, don't you? Yes, I suppose you could, but you wouldn't enjoy it. Figure out which you'd rather do... Blue Lagoon and shop, or Atlantis. Pick just one of these options and then enjoy yourself.