DDP does not have pricing for juniors for dining. The juniors designation on a package reservation refers to the resorts, not the dining. It exists to refer to those over the age of 9 (old enough for adult park tickets) and under the age of 18 (old enough to trigger the third adult charge in the resorts.)
DDP has two categories: 10 and up, and children age 3-9. Children under 3 are not eligible for the plan.
A child under 3 can share with their party at any restaurant, and can eat all they want free at buffets or all you can eat restaurants. If you purchase anything at an a la carte restaurant specificially for an infant, you will need to pay for it.
Children under 3 get free admission to parks.