Check the shore excursions page. It has renting cabana as on of the shore excursion option. However, since space is limited, the cabanas get sold out fast.

Yes, we have been twice on different cruise lines and each time there have been lockers that you can use at no charge. You simply lock them up and are given a key to hold while your on your excursion.

At all ports there are plenty of shopping opportunities near the port. Depending on the ports you visit, some of them have beaches within walking distance of the port. You can always get a cab that will take you to a local beach for much cheaper rates.

The beach chairs at the beach are complimentary.

Unfortunately, no, the beverage package only is valid for drinks ordered on board the ship.

Unfortunately, you likely will need to purchase a full-priced tour ticket to observe.

There is a thermostat in your stateroom which you can set to adjust the temperature in your room to your liking. The public areas of the ship will be cooled to the low 70s.