I think you misunderstand about health screening
None of those tests are to be done on the puppy. They are for the PARENTS of the puppy, and
needed to be done prior to the breeding taking place. The purpose is to ensure that they don't carry genetic diseases that they are likely to pass on to offspring.
There is no point in doing them on the puppy, because the results are at best inconclusive, and at worst meaningless, before the dog is (for most tests) a minimum of 24 months old.
Soo - prior to putting down a deposit, what you really need to be asking your breeder is for the results of the parents tests (BOTH parents). Since you say your mentioning it in respect of the puppies was 'met with some surprise' - rather than an explanation that it was the parents tests you should be intersted in - I'm not confident that the breeder you're talking to actually has any idea of what they're doing. In any case, I'd certainly recommend checking. And
if they've done none of those things, it's worth taking a pass on the litter, letting the breeder know WHY you're passing (so they might rethink for the future), and looking for someone else who takes the health of the breed and their responsibilities to do their best to produce healthy animals a bit more seriously. There ARE breeders in NZ who screen their breeding stock (though you may find there is more concentration on aortic/sub-aortic stenosis than on cardiomyopathy).
Just in case anyone tries to tell you that "those diseases don't exist in NZ" - it isn't true

They certainly do. Same goes if they try to tell you that there aren't facilities for testing - there are.