Not a breakfast with Scooby, but you can see Scooby and Shaggy on certain evenings at the 3 hotels.
We have only seen them at RPR, they went between Jake`s Bar and The Islands.
You don`t need reservations and you don`t need to be staying at the hotels to eat there.
The interaction with them is fabulous.
You can call the hotels nearer your trip and find out what nights they are there. They also have Shrek and Fiona and The Simpsons.