Hi Ashley!
So a January Winter Wonderland Disney vacation huh? Cool! And it's normally less crowded that time of year, which is always an added bonus :-)
Yes, the nations at the World Showcase are right next to each other, and on a less crowded day, you could probably stay on the World Showcase walkway and walk through all the countries in about 15 minutes, walking non-stop.
And yes to your second question. Disney does a masterful job of clearly identifying entree and/or snack items on all of their menus. This is especially true of the Quick Service restaurants, which normally have a smaller menu, as compared to a table service.
For more information, you can click here to go to the Quick Service Dining Plan (make sure to click on the PDF), and you'll see plan details and what generally qualifies as a snack item.
Have a terrific time. Enjoy the parks and all the good food!