i spoke to the lady at the place the twins are registered (August Models) and she said that NZ has such a small pool of commercial work, and too many children (babies).
She said that the best age to put them in for that kind of thing is about 5 years of age, because there is more work for that age upwards.
Reason I was asking her is because you pay a fee to have your child on their books, and then generally you don't hear much from them.
Pumpkin Patch apparently use a lot of inhouse staff's children, payment is by way of PP clothing (which is cool)
Unsure about JK?
Not much help but just some thoughts!