No, her N-400 will be denied, because a US citizen cannot apply for naturalization. Also, you always need to list your kids in N-400, don't misrepresent yourself as this may prevent you from naturalizing.
N-600 is optional, not required. But highly recommended. You don't have to do it immediately or ever. The only risk is if your daughter will have issues proving she's a US citizen in the future. That may cost more than N-600 (lawyer fees etc)