Yes you will be able to play it on your NZ/US accounts. Not sure if you can use the pre order dlc on your NZ account though.
edit: i have many games,including the show 14 purchased from the US store and have not had any issues.
Is 15 available on the NZ store ? 15 was available day 1 on the aussie store.
Ramone said that pre order for europe/AUS will be up any day now in the last stream. that was friday,thursday in the US.
The good thing about it not getting a retail release in aus is that it seems they can keep the price down to what i think is acceptable for a digital release.Most AAA games cost $99 on psn while The Show was $69 last year. I can get most retail games for $79 or less from a store.