If you are in NZ when your Residence is granted, it is activated at once, automatically, and your two years' travel conditions start running then, without your having to do anything extra. You do not need to leave the country and come in again.
A person’s first day in New Zealand as a resident is either:
the day their resident visa is granted in New Zealand; or
the day they are first granted entry permission on the basis of their resident visa, if they were outside of New Zealand when their resident visa was granted.
http://www.immigration.govt.nz/opsmanual/44894.htm
I understand that this visa turns into a permanent residence (PR) visa after 2 years (subject to meeting some conditions and applying for the PR visa). From the discussions I have read on this forum, this PR visa is actually permanent.
Yes, if you apply for PR and meet the conditions in one of the possible ways. Two years is the minimum time to pass - it may take some people longer than that to meet the conditions, depending on their circumstances and what they do.
http://www.immigration.govt.nz/migra...quirements.htm And yes, PR is permanent, as the law stands at the moment.
Citizenship - have it straight from the NZ government.
http://www.immigration.govt.nz/migra...omingacitizen/ http://www.dia.govt.nz/Services-Citi...nd-Citizenship
Residents can vote.
About a partner. INZ defines a partner as someone with whom you can prove a steady and ongoing live-in relationship. What you can apply for to start with varies with the length of partnership you can prove. If your partner is currently not in NZ, which sounds as if it's the case from what you have said, you may well need to look at the requirements for a partner-sponsored temporary work visa, which you can apply for with just a few weeks'/months' proof. Details here.
http://www.immigration.govt.nz/migra...milystream.htm Depending on the nationality of the partner, they may be able to enter NZ as a visitor without many formalities (visa-waiver country), or they may need to apply for a partner-sponsored visitor's visa, see here
http://www.immigration.govt.nz/migra...alvisitors.htm, in order to set up home with you and start to gather partnership evidence.
Once you have 12 months' partnership proof, your partner can apply for partner-sponsored Residence.
http://www.immigration.govt.nz/migra...er/default.htm