Hiya Wheels.
Refugees can come into the country in a number of ways. The UN refugee resettlement program is one, direct application from outside a country is another, application for asylum once landed in a country is another. There is no queue. Please repeat this to yourself - there is no queue.
The people on Manus Island have not been transferred to NZ as a group. In fact, the Aus govt has specifically declined to allow that. This particular individual was part of a deal between Aus and US for a refugee swap, but that had not been finalised as you note.
He was not in NZ b