Hi Donna,
The
Disney Dining Plan credits are based on the number of
nights in your
Magic Your Way Vacation Package. You will receive an allotted amount of credits based on the Disney Plan which you choose, and the number of nights in your stay. When you choose to use the credits is entirely up to you. If you decide to save enough to cover your breakfast on your check-out day, then you can definitely use them for breakfast at
Everything POP Shopping & Dining at
Disney's Pop Century Resort. In fact, the Disney Dining Plan credits do not expire until midnight on the day that you check-out.
To answer your second question,
Disney's Magical Express generally picks you up 3-hours prior to your flight departure time. That being said, on the day before you leave, you will receive documents with your specific pick-up time. You generally will have an envelope hanging on your resort room door, or occasionally they will slide it underneath your door.
Wishing you magical memories,
Kaylene