This is an old thread, using the old name of a visa which was already not correct then.
Your questions 3 and 4. When you apply for Residence under the Skilled Migrant Category, as you have, if you don't have a job offer from a NZ employer, about the last process the INZ Case Officer will go through is to interview you. This is what the interview is for.
http://www.immigration.govt.nz/opsmanual/43652.htm If the CO is happy that you are well prepared and have a good chance of employment in NZ, you get Residence. If the CO is not really satisfied, but thinks you have a slight chance, you are offered a Skilled Migrant Category Job Search Visa (SMC JSV), also known as deferred residence - the thing that used to be called SMC WTR - which allows you nine months in NZ to find a skilled job. If the CO finds you are not well prepared, you are refused.
5. If a person with SMC JSV does not get the offer of a skilled job within nine months, they have to leave NZ when their visa runs out.
Your questions 1 and 2. Here is an old post which explains processing.
http://www.enz.org/forum/showthread....690#post450690 Because of all the checking which has to be done, and the fact that the CO has to wait for replies from people who can verify that each piece of your evidence is genuine, there is no way to tell in advance how long it will take.
6. Use the Search button (top right). You will find there are many old threads which talk about cost of living, and different places in New Zealand.