I would consider the current COVID-19 protocols - restrict access and people numbers, handwashing/sanitising, regular cleaning of common areas and surfaces, PPE, social distancing, stay home if unwell, work from home if possible.

This is a thought provoking question!

I haven't though about the management plan at this stage however in answer to your questions:

Q1: use the appropriate L2, L3 or L4 responses for hygiene, distancing etc. The basics are unlikely to change.

Q2: my hypothetical is the Government response would never to be like the UK Plan. One of the goals of all the steps that have been taken so far is to protect the NZ health system which would be over run if Covid went rampant. Any future variants could overrun the health system and I don't envisage the government would abandon a successful strategy. Using this hypothetical we are looking at maybe 1-2 years before boarder restrictions ease right back, and even then we will still probably be inflicted with some sort of health passport.