did you ask if they can route you through CAN/Guangzhou in China? if you can find availability between DTW and CAN. Just checked and saw that there is space available on the China Southern Flight CAN-SYD but it leaves at 9:30 Pm which is before the NW flight from NRT arrives. There are other options to get there on Korean getting you in at noon. but of course im just telling you your options..not quite sure about availabilty. Not really sure how you would get between SYD and NZ but it shouldnt be hard. might be long..but getting down under is normally long anyways.