We try to answer everything :icon_biggrin:

From the top.... If your husband is applying for a work permit, then you need to apply for a work permit based on partnership. What that means is you will be granted an open work permit for the same length of time as your husbands, entitling you to work for whoever you want.

Your son will need a student permit, but you usually need to know the school he will be attending before you can complete the form. May well be better off leaving the student application until you know where you will live, what school etc...

For your mother it's not so straight forward. The only way she could live in New Zealand with you would be if you sponsored her under the family category. To be eligable, you need to have held residency for a minimum of 3 years prior to applying to sponsor her Any time spent on a work permit is not counted towards those 3 years.