The benefits of what you've got are pretty meaningless - yes you have a Skycouch seat (not all rows with the seats are sold as Skycouch rows) but with 4 of you unless you can find other seats for the 2 other people then pulling the legrest up will be pointless as you won't be able to lie flat with the others in their seats.

Are NZ is also very strict when it comes to seatbelt use in the Skycouch. They are under no obligation to give you a belt kit unless you've paid for the product, so even if you could find seats for the other 2 people If you do not have a belt kit you will get very likely by woken by them. Belt kits are given out as a NZ HVC benefit if they're allocated a Skycouch row but merely being in a row will not entitle you to a belt kit.