Yes, don't do Skycouch unless you are a petite short couple. It is no substitute for business class by any means. You can go NZ PE, but as you rightly pointed out you can sometimes buy fares in business for the same price on other airlines.
Given you mentioned Finnair/Cathay, that is a good option via Hong Kong (you might find more options if you book to Sydney and buy a separate ticket from Sydney to Auckland, which might be cheaper than the scarcer tickets on Cathay to Auckland, simply because Cathay and Qantas fly much more often between HKG-SYD than Cathay does HKG-AKL). You'll get more than enough to be BA Silver for a year. The other relatively cheap option is Austrian in business, but it does mean going Thai from BKK to AKL and that is an angled lie flat seat. Finnair/Cathay via HKG is fully lie flat.