My dear Copterin
Anything is possible and a J1 Visa is certainly a way of gaining entry to the US market for 2 years. Take a look at
Helicopter Adventures Inc based in Titusville, Florida and have a browse, you should find the J1 Visa page useful. If you like what you see, a phone call or an e-mail to HAI will answer your queries directly but I would establish that the school can offer you a place and meet your requirements before stopping your CPL training in NZ.
Good luck.
The Ferret