That's my understanding also. That when you notified them that the family composition had changed and the new baby needed to be added, your original visas would have been invalidated and you are now waiting for new visas (with the baby's) so that all the family can land together. It appears you have done what was necessary - you notified them of the birth before you landed, and added your child to the application. They may ask you for re-meds before they will issue new visas if your original medical exam will be expired before they can issue new visas. You might make an appointment to get those done so that you have the proof of it available when they ask as it's probable, because the original visas were set to expire on May 17th - that your medicals will expire then, too. Either that or your passports expire then - and then you'd need to renew those. But it seems as though all you're waiting on now is the baby to be assessed and then they will issue (new) visas to the whole family so you can land together.