1. surface segments do not count on OWE fares
2. trans-ocean surface is prohibited except for ex-Australia/NZ (not that you would want to do trans-ocean surface, but this rule allows including AKL/PPT-SCL on a OWE ticket)
3. buying from a TA in NZ is easiest, or you can get it issued by QF in AKL. It cannot be issued by AA in the US (if you do that, it prices at the ex-US price), however you can have the ticket set up by the AA RTW desk. I don't think AA has an office in NZ (they do in SYD).