The VA service would have to leave earlier (say around early 6am or slightly earlier) than NZ's early service to meet up with the UA service. This would also allow VA to pick up Queensland connections from UA's SFO-AKL service as well.UA916 is a 1450 departure from AKL, arriving SFO 0705. (note: moves to 1550 as of this weekend)
Air NZ already run an 0810 departure from BNE, arriving AKL 1430, so if VA were going to do something to pair up with UA916 then it would end up mirroring the NZ service.
TBH I'm thinking this would only be a minor consideration in the general scheme of things, and it's going to be based on how much traffic they can get in both directions.
I've also why I've pretty much stated earlier that the UA partnership would play a minor factor (at most) in VA's decision to return to the major NZ cities, as there are numerous other factors (plus with basically all Australian states going around with private/public aviation funding to try to attract international services back to their states)