Ahoy, Mark!
You're going to have a SPOOK-tacular time on your Halloween on the High Seas sailing. It sounds to me like you've been researching all the fun you'll have onboard in October, and you've come to the right place for more information about what's available on the Disney Fantasy.
The Royal Court Royal Tea is offered, for an additional fee, for cruisers ages 3-17 when accompanied by an adult (Guests ages 13-17 pay the adult fare). Unfortunately, adults are not allowed to book this event unless they have a prince or princess below the age of 18 with them. But, you will be able to dine with some of your favorite Disney Junior Pals like Jake, Sophia and Doc McStuffins (always subject to change) at the Character Breakfast offered on the Disney Fantasy. Tickets are required, but there is no charge. You'll reserve your spot in "My Cruise Activities" once your advance booking window opens up. If you are Silver, this date is 90 days before you depart.
I believe the High Tea you are referring to is the one that was offered at Palo a few years ago. Currently, Palo offers a delectable brunch and dinner and a one-of-a-kind cooking class,
"Palo Be Our Chef." This experience, only offered once per cruise, allows you to prepare, cook and sample delicious dishes right alongside the Palo chefs. And that's not all! You'll also go home with unique keepsakes including a personalized Palo Chef's jacket and nametag. You may also be interested in a culinary experience at Remy. Remy offers dinner along with the Remy Champagne Brunch, Remy Dessert Experience and Petites Assiettes de Remy (first night of the cruise only). An additional fee applies to all Palo and Remy experiences, and reservations can be made once your advance booking window opens up (Palo Be Our Chef must be made onboard unless you're sailing Concierge Level).
Good luck with your plans,
Nancy