Commando; your only half right.
Yes, Freedom and Air NZ have definately (according to pilots at SJ) combined their seniority lists (with SJ tagging on the bottom of ANZ as at the beginning of this month, I think).
Freedom pilots (along with all incumbant ANZ pilots) have first rights to all positions within ANZ before any external pilots are hired. (Thanks to old ANZ pilots wanting commands at SJ from what I understand!!)
Air NZ and Freedom have also combined their recruiting processes and you may be now offered a position at either ANZ or Freedom depending on where the vacancies are - and will be paid accordingly. A new FO at Freedom is paid somewhere in the late 40's, early 50's with an OK allowance package (OK in terms of not having to live on the streeets!).
IF you are taken on by ANZ (ie no Freedom pilots want to come across), you will still be taken on in SO positions, and if you get taken on by Freedom, you may bid for any positions in Air NZ with the most likely positions being available on the 747 as SO's (more senior pilots than any new boy will want the FO possies at ANZ because of the pay difference!).
I'm not sure how many SJ pilots are jumping ship (so to speak), but I understand from mates already interviewed by ANZ that there are already quite a few external applicants sitting on 'YES' letters with no start dates......