I'm afraid quite a lot of this will not count as far as INZ is concerned. They only recognize work experience as skilled AFTER your qualification is gained (so, after graduation). Part-time work (for instance, while studying for another qualification) can be totted up to find what would be the equivalent full-time amount, BUT it won't be counted if you should have had a visa or authority to work, and didn't have it.
http://www.immigration.govt.nz/opsmanual/30571.htm
It looks as though some of (2) would count (the part after you graduated). And the part-time part of (3) might count, as long as you were in a 'comparable labour market', or your firm counts under SM11.10.1 b
http://www.immigration.govt.nz/opsmanual/30570.htm, and as long as you were legally entitled to do that work in that country while employed by them.