Would NZ have been as rabidly anti-Japanese as Australia was at the time?
Some sections of Australian society, most notably the RSL were rabidly anti-Japanese but the majority of our society was starting to change. Personally, I put it down to the advent of TV and the showing of Japanese kids' TV shows such a "Shintaro" and "Secret Samurai". It was interesting to see how attitudes were changing in general. Japan was starting to seen as a new market and a source of investment. I remember though, the RSL blocking the purchase of Toyota Landcruisers over Landrovers in the late 1970s, despite the Landcruiser being cheaper and in many ways a better vehicle.
I'd assume that the Kiwis were much less anti-Japanese. Having been less involved in the war against Japan, than the war against Italy and Germany, they would not have had the personal involvement than Australia had in the PoW issue and the hysterical fear of the "Yellow Peril" from Asia. I knew of old diggers who refused to purchase anything made in Japan. I served with a fellow digger whose family had suffered a PoW and who'd hear nothing good about Japan or Japanese.
I think a landing boat is a great idea for the RNZAF in this period. With their responsibilities in the South Pacific, where runways were relatively rare and few it would be an ideal solution. Martin Marlins though were more likely IMHO than either Shackleton or Shin Mewai.