Unless these entry level engineers have families, there's no good reason to be paying $5-6k a month for rent, you can easily find a decent place of your own for under $4k, even $3k if you're patient.
my total monthly expenses are roughly 3500/month so I am able to save almost 50% of my post tax income.
and the USD salaries would put you in the very very top earners of the population. Though sourcing enough devs here would be tricky for anything beyond 10 people if you actually wanted to outsource to NZ.