You just summarized my endeavors to a tee!
My guess is a lot of info has been literally scrubbed off the web. Who knows how many witnesses are missing,ala Clinton style, and what the real story is.
This is going to take a lot of investigation and may take a while.
Scrubbing is still going on as evidenced by the post on Ann Dunham’s wiki about the East West Center that lasted less than 24 hours. It’s also convenient that so many people who could have some knowledge of events are dead. Even one of the two teachers of the Russian language class has died, she passed away in 2005 but not all the students who took that class could be dead. The question then is why has not one of them come forward? Not a single person has come forward with any memories of the student Ann Dunham in classes for the 1960 semester.
Alice G. Dewey has certainly had plenty to say but if she mentions Ann and Obama Sr then her testimony is hearsay as she wasn’t on the faculty of UH until 1963 and yet info on the 80 year old Dewey is sparse as well. It certainly raises even more questions!