Rule number 1 of cruising: don't stress, there's no way of doing everything in one cruise.
You will have a great cruise with or without Palo, with or without a dolphin encounter, with or without the one specific SPA treatment.
Enjoy the time you spend with your loved ones, take pictures, have the MDR meals walk around the Ship, meet characters, take a swim, order some roomservice or not, have unlimited food and ice-cream. Just relax and have fun! If you focus on all must-do's you are setting yourself up for disappointment.
Practically: half of the time slots in Palo are only available for booking once on board, so even if you don't get the time/meal you wish online, just give it a shot at embarkation day. No reason for stress.
Only stress is: bring you id (BC+photo id or passport) as no id = no cruise and be on the Ship well on time. All other things are "take as they come" and you will have a blast.