The known adults who correspond to the young students are circled beneath the corresponding child. How and who and why, I have no idea. The adults are not identified by name.
And don’t we find it curious the adults are NOT identified.
Here’s something related to your “Anna” theory:
“A Washington Post news article stated: Late in the summer of 1960, at the start of his second year and the beginning of her first, Obama and Stanley Ann Dunham met in a beginning Russian class. He was 25; she was not yet 18. She called him “Bear-ick,” too. He called her Anna.”
http://kalaniosullivan.com/BO/BOBackground.html#PASSPORT