NJ FamilyCare: Can I apply for my unborn twins without applying for myself?

I’m pregnant with twins in New Jersey and currently have private insurance for myself. I am not trying to apply for Medicaid for myself—only NJ FamilyCare coverage for the babies.
I understand that NJ FamilyCare uses different income limits for pregnant adults and children under 19. I may not qualify under the pregnant-adult limit, but the babies may qualify under the higher children’s income limit once they are born.
Today, an NJ FamilyCare representative completed an application over the phone for my unborn twins, allowed me to select UnitedHealthcare Community Plan, and gave me a new confirmation number. However, when I was transferred to another representative, she could not locate the new application and seemed confused about how I could apply only for the babies without applying for myself.
Has anyone in New Jersey successfully submitted a child-only NJ FamilyCare application before their baby was born?
Was the application processed before birth, held until delivery, or did you have to apply again after birth?
Did Medicaid cover the babies’ hospital charges retroactively to their birth dates?
What did you tell the hospital billing department while the application was pending?
How long did approval take?
I’m especially interested in recent, firsthand NJ experiences or information from NJ FamilyCare enrollment workers. I’m not looking to conceal income or household information. I’m trying to understand the correct process and avoid a gap in the babies’ coverage.