Hi Victoria!
Welcome back to 
planDisney! It's great to see you with another question about an upcoming 
Walt Disney World adventure. I'd be delighted to assist you today.
When dining plans became part of our world again, they brought a few updates, one of which was that quick-service meals can no longer be exchanged for snacks. Any remaining quick-service meals must be used at quick-service restaurants. In the past, I purchased a drink and a breakfast sandwich using a quick-service meal at a Starbucks location, but this is at the discretion of the Cast Member, so you'll want to ask if this is allowed before placing your order. Some breakfast entrees can be wrapped and taken on-the-go to consume later. 
Starbucks handcrafted beverages are great for "snacking" on a dining plan. Did you know that any size beverage (even a Trenta!) is just one snack on your dining plan? You'll find the same at my favorite Walt Disney World java joint, Joffrey's Tea & Coffee Company. One of my favorite Disney snacks is an iced vanilla latte from a Joffrey's kiosk. 
I hope everything works out for you, Victoria. If you're looking to make the most of your quick-service meals, I recommend 
Columbia Harbour House at 
Magic Kingdom Park, 
Docking Bay 7 Food & Cargo at 
Disney's Hollywood Studios, 
Satu'li Canteen at 
Disney's Animal Kingdom Theme Park, and 
La Cantina de San Angel in 
EPCOT. They're some of my family's favorite spots. Thanks again for sending your question to planDisney, and don't hesitate to reach out if there's anything else we can help with as your vacation approaches. 
Have a magical day,
Betsy