According to at least one source Lefty O'Doul was not a member of the team. Further research has O'Doul as the coach.
http://www.baberuthcentral.com/babes...trip-to-japan/
Only 15 players made the roster and you seem to have all but 2 identified.
http://www.baberuthcentral.com/wp-co...naturesopt.jpg
One of the signatures seems to read Johnny Kerr (panel 4 after Clint Brown). If it is Kerr, then things get interesting. The All-Stars stopped over in Hawaii and played a game in the islands.
https://books.google.com/books?id=V_...20kerr&f=false
So, the signatures could be from members of the Hawaii All-Stars or as you stated, wives and other dignitaries.
Good luck.