Bart, about the jellyfish, you can encounter them at any time, but the ones you might have to worry about are those you can't see. During that time, it's still the season for thimble jellyfish larvae, which can give you a rash, called "sea itch" or "seabather's eruption." Some people call them "sea lice" (erroneously. Sea lice are actually parasites that attach themselves to marine life.)
Most people don't react strongly to sea itch. Generally speaking, Benadryl will help, as will cortisone creams applied topically.
Portuguese man o' war can be a problem anytime there is an east wind (blowing from the ocean to the shore.) In that case, warnings will be posted. If you see them on the beach, give them a wide berth. They'll look like bright blue or purple bubbles. Tentacles are often blue, but sometimes clear.
The resort is really nice. We've stayed there several times. Not necessary to have a top floor unit, as we have never had one and have never been bothered by noise. Views don't matter all that much, as most units look down at the recreation area.
One thing to know before you go, unless you like really high-pressure, screws-to-the-temple timeshare "presentations," STAY AWAY. Don't let them talk you into it - it was one of the most unpleasant experiences we've ever had at a timeshare. They say it will be "90 minutes," but don't count on getting away any sooner than 3 hours. They insult and badger. 'Nuff said!
They used to give a coupon at check-in for an Everglades tour. It was very reasonable, and a great time.
Time your trips to the beach to leave around 9-9:30, so as to miss the morning rush hour, and plan to pack up and start your return for no later than 2:30, or you'll be stuck in horrendous traffic. I-95 becomes a parking lot.
You're going to have a great time. Don't miss Butterfly World - expensive, but worth it to see the most unusual butterflies in their simulated, natural habitats. Also huge lorikeet and hummingbird displays.