Doesnt matter what their registration status is - if they havent been inspected and approved the foal wont get registration rights in that registry
For example, there are several Hanoverian stallions that were never inspected / approved AHA, but were approved Old NA and/ or GOV and / or RPSI so those are the registries the foal would be eligible for
You would have to go to both registries and see what the requirements are for breeding. Is the mare approved in the Brazilian Warmblood book or is the stallion approved by the Dutch Warmblood registry? You could see if the mare can be put into the Brazilian Warmblood mare book, then the foal could be a Brazilian warmblood, I believe.