Hi Mara,
Normally, I would recommend that you book
Donald's Safari Breakfast as early as possible (on a non-Extra Magic Hours morning). This would allow you early access to the Park and you'd be done with your breakfast right about the time the attractions open. The
Kilimanjaro Safari is located near there, and it is great to ride it right away (as the animals are most active then).
However, if you are heading to the Animal Kingdom early for the purpose of hitting the Extra Magic Hours, then I would do a later breakfast. You'll be able to ride some of the most popular attractions before the crowds really pick up. Instead, I'd reserve a breakfast around 10:00am or so and consider it brunch. You can then plan on an early dinner.
Our family loves Donald's. The food is delicious and the character interaction is fantastic. Be sure to try the "Jungle Juice", it's great.
Have a magical vacation,
Kaylene