Hi Julia!
Disney Dining Plans are a great way to pre-budget your meals so you don't have to think of menu math when enjoying your Walt Disney World Resort vacation. To be honest, I haven't used a Disney Dining Plan in a few years, so I recently purchased the classic plan for a one-night stay. For #resEARch purposes.
The beverage part of each meal entitlement may be redeemed for standard choices like tea, juice, soda or coffee.
New for 2018, each guest may select a specialty beverage to wash everything down, like a milkshake, a fresh smoothie, premium hot chocolate, and yes, alcohol if the person is of age. (Note that it's one or the other, but that you can certainly order a special beverage and pay out of pocket for a regular drink.)
I'm a very big fan of breakfast bubbly and Disney drinks; after all, you're on vacation! Your children will technically be classified as baby adults in the dining system because they are under 21 years of age, so an attempt to purchase alcohol using their dining entitlements would flag and pause the order when attempting to pay. (This is done more-so to make sure those who are underage and traveling with say a high school group can't get into trouble, and not to specifically single you out.)
Another way to customize your Disney Dining Plan is if your kids are lighter morning eaters, together they could redeem one meal entitlement on something huge like a breakfast platter (found at most Disney Resort Hotel quick-service restaurants, this feast is usually waffles, eggs, bacon, sausage, and a biscuit) AND select a fruit smoothie as their beverage, then share everything. The one Quick-Service meal entitlement that was saved can be turned into three bonus snacks somewhere else!
We'll See You Real Soon, Julia!
~Kristen