Jason, fighting vehicles are a convenient term. Do you really think for instance that your LAV's could stand up to an M1A1 Abrams? They are completely different levels of capability. The NZ Army acquired it's 105 LAVIII's for the purpose of providing armoured mobility for it's infantry forces.
It is NOT an Infantry fighting vehicle in the sense of a Bradley or Warrior, or for that matter M113AS3/4, due to it's lack of cross-country mobility placed on it by virtue of being a "wheeled" vehicle.
As to Australia's ASLAV's, though they are type II LAV's, as opposed to your Type III LAV's, ours have recently been upgraded with new thermal imagers, electric turret drives, new laser range finders and new fire control computers and represent a newer generation than the equipment fitted to the NZLAV's. Both NZ and Australia's vehicles (ASLAV-25's) are equipped with the SAME 25mm cannon and 2x 7.62mm GPMG's.
Australia operates 180 of the ASLAV-25 variant. We also operate ASLAV-PC variants and ASLAV support vehicles which are equipped with the new Kongsberg remote control weapons system, which is a capability NZ is entirely lacking.
As to the OPV's, well the 25mm Typhoon is not a radar guided close in weapon system like the Phalanx and would be extremely lucky to hit an anti-ship missile not matter how good the crew is. In addition Bushmaster Cannons are not particularly fast firing weapons like the 20mm Vulcan cannon fitted to Phalanx CIWS. Their max firing rate is around 120rpm, which is slow even compared to 0.50cal heavy machine guns (around 400 rounds per minute). They are simply not designed as a CIWS weapon. Accept fact.