It would be cute if older kids could somehow man a booth for other kids. They could construct their booth using a crafting table or I guess just buy one. Then they could sale drinks and snacks. I miss the little oven for kids. Sometimes I would have them make muffins before school. I'd have my young sims get up and make it and then the adults would also eat it. Also, I seem to remember they didn't ever rot or anything so you could just keep a lot in your inventory for a snack on the go. I also seem to remember that if a sim had any fruit in their inventory they used to eat it automatically if they were hungry enough. I don't think they do it now, but I like to keep some fruits in there and make them eat it sometimes. I wish we had more foods that didn't go bad for a snack on the go. I want kids to be able to help make some simple foods.
I like the idea of lemonade, milk and juices. I also wish they had something more substantial and filling but quick to drink. Kids could drink protein shakes or a hot cup of soup or something. I know in some countries the have this sort of drink that is a snow cone but it also has condensed milk, fruit, bits of jello and for some reason I don't get, it has some sort of sweet beans in it. It is called Mix Mix. It is fast to make and probably pretty filling.
I had one of my sims recently ask for her favorite drink at the bar and it was just a vanilla soda or something, So even kids could drink that, no problem.
There needs to be something that a sim can just chug in one gulp and it completely fills them up so quickly so they can party and have a good time. But also they might get a moodlet from it or get sick randomly, because that does happen if you eat too much too quickly. They could get the hiccups or burp and embarrass themselves.