To answer the question - Disney has said it will allow people to only use as many credits as they have people on their card at one time. So if you have 3 people on your meal plan, they might not allow you to order 4 meals on the dining plan at one time. Or they might. Until you get there, you won't know. And even then, you might be allowed once, but not a second time.
Technically, you aren't allowed under the rules of the plan to take a CS meal you don't eat and transfer it to your child not on the plan. Practically, Disney has no way to enforce the rule unless you try to order all 4 meals at the same time.