H1-B Applicant qualifies for waiver,But dependent don't have any previous Visa history

The primary applicant qualifies for waiver, but dependents (spouse +10 months old kid ) doesn’t have any U.S visa issued in past. Will dependents qualify for dropbox or they will have to attend interview separately. Also, how to take separate appointments with same receipt number… I(Primary applicant) booked the appointment, since the dependents were declared all together so I got single slot for VAC for all three… Do I need to cancel and re book separately for me and dependents?

1st time US visa applicants will need an interview.

Just call VFS and they will guide you.