if you are flying to YYZ on AC, then yes, it is THE place to be, especially since you're already in the correct terminal. If you are flying on UA or US, then you won't have access to it. Hence, the refundable ticket trick.

Well if you can get in the NZ lounge (same terminal as AC) then I would definitely choose that over AC lounge.

Not recommended.

a) Refundable tickets likely to be quite expensive on NZ, and expect to get the refund in 6-8 weeks (ie you'll incur interest costs of lost interest/investment earning costs as well as having to front up with the money in the first place). Checking some fares at random I see about US$1134 which has US$300 cancellation charge and must be cancelled before travel commences (does checking in count?) - an expensive lounge visit!

b) last NZ flight out of LAX is 2215, so if you want to cancel you'll need to do so early than that (and before boarding starts unless you want to inconvenience all the other pax on the flight)

c) Air NZ will be passing on your info to NZ immigration when you check in as required for pre-clearance. Your record will be noted in some way if you then change your mind about travelling. May or may not matter to you in future travels.

Refundable ticket on NW allows access to NZ lounge?