I will correct myself here but I won't delete my original response in case the info is useful for other people.
I completely misunderstood your situation, looks like your wife does not have her visa yet and your child was already born.
To answer your question, if you are completely sure that your child does not qualify for a CRBA then the best option will be to file for IR2 (the regular i130 form) and try to expedite it, someone with more experience can guide you regarding this in case is possible to expedite.
Original response:
Does your wife already has her immigrant visa with her? Physically? If so, was the visa issued the same, before or after the child was born? I believe If the visa was issued before the child was born then you should be able to bring your wife and your kid, the infant can travel without a visa. Just make sure to bring your child birth certificate at the port of entry here in the US.
Also, I don't think the interview date is important, what matters is the date of the visa was issued, sometimes or many times the visas are issued days after the actual interview date.