As for purchasing a ticket before the child is born, we did just that for a DONE4. We decided to wait until we found out the sex of the baby before issuing the tickets - once we knew the sex we knew what the name would be. We could have just done it with an initial instead of the full first name (at least back then).
The interesting thing was that we started on the ticket before min-alect was born. Most of the time checking in with 3 tickets and then pointing to mrs alect's stomache was humourous. Only the CX agents in HKG were a bit baffled by the whole concept and lost until I said we can just throw away the coupon for the INF for that segment.
We have kept the INF BP for QF F MEL-LAX in her "baby book" as a momento she travelled in F before birth.