I can see what others are saying in it being similar to other hyphenated names and people mixing them up. But I don't think I would let that worry me. I mean if you are going for something easy to remember just go with Child A (that is not the purpose of a given name).
If people say her name wrong she will I am sure be able to correct people - as we all do now with our own names.
Go with the name you like best!