I have scanned an old photograph from early June 1930 which shows the group at some Hollywood studio possibly with two movie stars. I cannot recognize the two prominent persons. Perhaps someone could know who they are.

I do know three persons: the man in the middle is Felix Salten (writer of Bambi) from Austria, and to the very left is Georg Meri from Estonia (father of president Lennart Meri); standing next to and almost behind Meri is Urho Toivola from Finland.
Both Salten and Toivola wrote a book on this journey. I have translated Salten’s book Fünf Minuten Amerika (“America in Five Minutes”) from German into Finnish and also read Toivola’s book Aurinkoista Amerikkaa which only exists in Finnish.
(Possibly the photograph also includes the following persons: Karl Friedrich Baberadt, Sven Backlund, Taeke Cnossen, Ernst Feder, Alfred Herrmann, Georges Kirkoff, Sigurd Konstad, Jaroslav Koudelka, Erik Møller, Albert Oeri, György Ottlik, George A. Finch, and James B. Wharton.)