My guess is the Dutch will have no units but the IPCs will go to either ANZAC or UK (or both?)
There might be a few token units but thinking historically, the Dutch didnt have much of a force in the South Pacific, (which is why it was such easy pickings for Japan) and the responsability to protect it fell primarily on the UK and ANZAC.
I would expect most undefended territories, maybe a small garrison controlled by the UK or ANZAC.
Also@WILD:
This will also allow the Japs to build up income. At the same time the Japs will be taking parts of Russia (uncontested), and invading China. When the Dutch Islands are liberated I would think the income would be given to the Anzac regardless of who does the liberating for game balance.
I was under the impression you could not invade Russia at all in AAP40.