Here is some of what was mentioned in terms of breakfast:
BREAKFAST AT LEAKY CAULDRON AND THREE BROOMSTICKS
The Wizarding World of Harry Potter vacation package includes a breakfast at both The Leaky Cauldron in Diagon Ally and Three Broomsticks in Hogsmeade.
Guests are able to schedule their breakfast times when booking the vacation package. If the time you have scheduled doesn’t work for you, just visit the restaurant and ask if you can change your time. They tend to be very accommodating and understanding.
The meals include a voucher for each guest in your party to order a breakfast meal and drink from the menu. When we dined at Leaky Cauldron our total would have been over $70!
And here are the breakfast menus at Three Broomsticks and Leaky Cauldron so you have an idea of the items available:
I would definitely run the numbers before booking a package at UO. It is often cheaper and better to book the room separate of the tickets, especially if you get an APH rate for the room. Booking separate also makes it easy to cancel or change your dates. The tickets do not need to be purchased before you arrive and you can cancel the room without penalty up to 5 days before arrival...