This depends on work flows through immigration New Zealand and the type of visa you applying for, but generally months.

Very. The rules are complex and can be difficult to negotiate and understand.

Licensed Immigration advisors and practising lawyers.

This will depend upon your visa application pathway and eligibility. You should obtain a professional assessment to ensure that you can meet not only the criteria but you can also evidence that criteria through the appropriate documents.

Anyone provided they meet the relevant criteria for the type of visa that they are seeking. Again it's important to take professional advice before launching an application.