His mother must have had connections with Vital Statistics Office and paid bribed them to print the announcement in two newspapers.
Hardly necessary. His grandmother would just have filed a "home birth" certificate, fudging the date a little. The filing of that certificate would have triggered the birth announcement, just as one filed by a hospital would. The home birth aspect would be reflected on the long form Certificate, but not on the short form Certification.
The purpose of the "little deception", to have the baby be a US citizen.
No, his mother was probably still in Kenya at the time. The grandmother had the wherewithal to file the false docs with the State of Hawaii.
Hope this helps.