“So he arrived in Hawaii on his own passport and was probably unaccompanied.”
I have never seen evidence that Barry travelled between HI and Indonesia unaccompanied. Just because he had his own passport doesn’t mean he was unaccompanied. There are pics of Madelyn in Indonesia visiting Barry as a child and she could have taken him back with her at the conclusion of that visit, for example.
Madelyn visted Indonesia after Stanley Ann Dunham gave birth to Maya. ‘Barry’ was still in Indonesia months AFTER that visit.