Do not use the Nexus kiosk if your iris scan hasn't been done. You are not able to use Nexus in 'air mode' if you don't have it. They may very well revoke it if you try.

Just clear using the APC kiosks as a group - as a family, you can use one declaration card. Then, once cleared, you can access the Nexus office and get your iris' scanned. Or if you are going to be downtown, the office there can do them as well, IIRC.

And if you plan on traveling to Canada with your family again, make sure you get them all Nexus before your next trip.