I think you are correct. It was not a legal marriage contract under HI law.
See: HRS 572-1 section 3.
“The man does not at the time have any lawful wife living and that the woman does not at the time have any lawful husband living;”
Obama Sr already had a wife and children in Kenya which he may have kept secret at the time from Ann Dunham. Either way, the marriage was invalid under HI law.
The fact SHE made the claim in her divorce proceedings THEY were legally married, does not make it so. It could not have been a valid marriage under HI law, since he was already married.
Seems like a person would have to know whether BHO’s first marriage was recognized by Kenya. If it was a tribal marriage it may not have been legally recognized in Kenya, in which case HRS 572(1)(3)’s meaning of “lawful wife living” would come into play. I would imagine it would depend on whether the marriage was recognized as a legal marriage by the Kenyan government.
Trouble is, we can’t know that without asking Kenya. And to do that would require discovery, which no judge has been willing to grant.