I've been rereading this forum and others looking at options for the RNZAF if the upcoming election brings a new group with different priorities to the table.
Without causing kniptions amongst some mods I want to revisit the discussion of how transport service can be provided at a reduced level. The discussion has centered around high end replacements for the existing Hercules and Boeing fleet with A400 and KC46 mooted as plausible contenders. Such replacements come with big dollar price tags of more than NZ$200 million per airframe. A one for one replacement would cost at least NZ$1.4 billion just for the planes.
IMO there are some inherent issues with the ideas you posted.
One of the first is just the raw numbers of transport aircraft, or the lack thereof. A fleet of 4 aircraft (following the Rule of Threes) should be enough to provide a minimum of a single aircraft that is either available for operations, or on deployment at a given moment. Depending on training, operations, maintenance and upgrade schedules, that single aircraft could potentially be surged up to three aircraft. However, responsible contingency planning can only count on that one single aircraft. That itself becomes problematic because things do go wrong, malfunctions happen, and very suddenly that single available aircraft could be forced out of service leaving no aircraft available for a mission. That is something which happened with the RNZAF actually, during some of the unrest in Thailand.
At the time, the RNZAF airlift fleet consisted of five C-130H Hercules (prior to the current upgrade programme) and a pair of then recently acquired B757's which were undergoing conversion. Due issues with upgrading and replacing the RNZAF airlift fleet (which I blame the Gov't of the day and prior gov'ts along with MFAT for) out of a total of seven airlifters in the inventory, only a single C-130H aircraft was available for a mission. The mission itself was to fly from NZ to Thailand to evacuate Kiwis trapped in Thailand during/by the unrest. Unfortunately what happened was that the ~50 year old C-130H had a malfunction either on the ground, during takeoff, or shortly after takeoff and had to immediately return to base. As a result, the RNZAF had no functional airlifters to utilize and meet the gov't directed mission of evacuating Kiwi citizens.
Going with such a small number of replacement airlifters can easily lead to a single point of failure for future lift missions due to aircraft functionality and availability. Especially for such a widely used role like airlift/transportation.
Now I do like, and have on multiple occasions advocated for a light to medium multi-role airlifter which can provide airlifter for smaller, lighter cargoes over shorter distances, and as needed or desired also provide an MPA capability, etc. Again however, quantities count. If four C-295 airframes were purchased as suggested, that would still limit the number reliably available to only one. That means only one C-295 which could be used for airlift, OR MPA, OR SAR, etc. at any given moment. Again, such a lack of numbers (especially given a split fleet of airlifters) means the multi-role capability becomes less important, since so few will be available at a given moment.
Three other factors which IMO were overlooked in their importance, especially for a force like the NZDF. These factors are airlift cargo load weight, range for a given cargo load, and size/volume of a cargo load.
Given NZ's location, apart from airlift missions from one part of NZ to another, NZ can expect many airlift missions to be of strategic as opposed to tactical distances. This will generally require a larger airlifter to ensure sufficient range for more missions.
Relating to the range is the cargo load weight, and especially the range for a given load weight. IIRC studies done by the US and Oz determined that for many airlift missions, their C-130J's were flying half empty or with even less capacity used. This was one of the drivers behind the development of the C-27J Spartan. Now I can certainly believe that a similar situation exists for the RNZAF, where often the C-130H's in service were not 'full' for many airlift missions. However, there were certainly times when more/most of that capacity was used. Also relating to that would be how much cargo weight a transport can carry a given distance, with most of the larger transports have both a greater max cargo, but also greater range for either a useful cargo load, or greater range for a cargo load of a given weight. To provide some numbers, according to the USAF C-130 fact sheet, a C-130H has a max normal payload of ~16,590 kg, with a max range at normal payload of ~1,050 n miles, or ~1,933 km. That max range can be problematic because the distance from Auckland to Sydney is ~2,155 km. For even smaller airlifters, with both less range and cargo capacity, the situation would be even worse.
Now for the importance of being able to carry out-sized loads. While NZ does appear to be looking to expand the sealift capability, and that is a good thing, for all the advantages sealift has, there are some distinct limitations. The two relevant ones when measured against airlift are speed, and access. The amount of cargo which can be delivered in a ship for sealift naturally dwarfs the amount of cargo airlift can feasibly deliver. However, it can take days or even weeks for a vessel to make the transit from the embarking port to where the cargo will ultimately be delivered. If speed is required, airlift is much more appropriate. Delivering an entire company of LAV's and associated personnel and support should go via sea, but if a single replacement LAV or NH90 was required, it would be both too slow, and too inefficient a use of resources to ship that cargo via sealift (unless commercial shipping could be used). Relating to that, the cargo's destination might be somewhere that is not reasonably accessible from the sea. Afghanistan comes to mind, where some supplies were shipped over land, but in very large convoys which slowly brought in large volumes of cargo. Cargo was flown in if needed quickly, or if the destination was inaccessible by road. With that in mind, NZ kit like the NH90 and NZLAV basically cannot be delivered by even the C-130 because they do not fit without being basically disassembled. If memory serves, the NZLAV also exceeds the max payload for a C-130, as well as being too large. What that would basically mean is that if anything the size of the C-130J were selected as the replacement for the RNZAF C-130H, then deployment and support of NZDF NH90's and NZLAV's would be confined areas the RNZN can get a ship either to port, or for a beach/amphibious landing unless the NZDF receives outside support. To give an idea of the potential utility in having an outsized cargo capacity, the RAAF currently has 8 C-17 Globemasters. Before deciding to get the C-17's, Australia had leased An-124 transports to airlift outsized cargo into and out of Afghanistan. Given the limitations imposed on when, where, and how the leased aircraft would be available, the RAAF felt having an organic outsized cargo capacity was important. Or at least important enough to drop what is likely more than $1.6 bil. in flyaway costs.