Yes, the missing week in the National Archives of foreign arrivals to HI is absolutely KEY. There's no way to call it merely a coincidence; no other week is missing. Likely scenario: Stanley Ann had her baby in Kenya, and as soon as he was old enough to travel she hightailed it to HI.
There are many dots that can be connected to validate what you state.
How would he know his own birthdate? I have always relied on the memories of others.