Regarding Gun Confiscation: If New Zealand collectively told their government to pack sand and refused to comply with confiscation measures... I doubt the US would go quietly. There would be rampant disobedience from rural areas. Urban areas? The people who would comply already don't own firearms.
In 50 years, however, I see this completely changing so I think even the core purpose of the 2nd Amendment will be usurped. Who cares if a bunch of rural hicks, who are 20% of the population, are armed with a bunch of 60 year old rifles when the beat squad are drones and those terrifying robot dogs that Boston Dynamics has shown? Also, we're probably (even more of) a Chinese colony by then, so it's dead in the water anyway.
To me, it's not a matter of if mass confiscation happens... it's more so when.