The way the Child and Dependent Care credit works is that if you have two or more dependents under the age of 13 (you do), up to $6,000 in child care expenses qualify for the credit, less any FSA contribution. The actual credit is 20% of the difference between the expenses and the FSA amount.
It does not matter if you spent all the money on only one child - you still get the benefit of having two (or more) children under the age of 13.
When you come to the screen entitled ""Here's what we have so far" and you see that all three kids have $0, when you add money for one kids, it may show up on others was well. So long as the 2441 is correct (The actual credit is 20% of the difference between up to $6,000 in expenses and the FSA contribution), it's OK.
