1) Entirely depends on what passport you hold and where you have an unrestricted right to work. To go for the UK programme, you must have an unrestricted right to work in the EU. If you hold an NZ passport or have the right to live and work over there, that would be an option.
2) It doesn't really make a difference. Apply now if you think you are ready - CTC will offer you a number of selection dates so you can just go for the one that suits best.
3) Phases 2 and 3 are now both done on the same day. You must pass the aptitude tests and group exercises in the morning to progress through to the interview in the afternoon as I understand it.
I suggest you look at the CTC website as you will need to do your research before applying.