I would go on your anniversary (if it falls during the cruise), and not worry about which restaurant you'll miss. Palo is a better choice than any of them.
If you really want to see all three, you can book Palo for later in the evening, if you have the early dinner seating (or vice-versa). That way, you can go to your restaurant, have a drink or an appetizer, get a feel for its particular ambiance, then go have dinner at Palo.
IMHO, people stress about which night to dine at Palo entirely too much. Missing a restaurant is not that big a deal. There is so much to do and see during the entire cruise, that you'll never be able to do and see it all. With all things, as with dinner, choose things you'll like and enjoy them without worrying about what you might be missing. You'll drive yourself crazy wondering about what you're not doing.