"O" might be Tyrone Power, or Walter Pigeon, but doubt they would be seen in a dive like this. More like a Bendix ("I")/Life of Reilly kind of place. The guy who made a joke of my hero Babe Ruth in his biopic. Stuck his tongue out while batting.The horror. If I had of run into him I would have challenged him to a duel to defend the late Bambino's honor. They gave the good biopic to Gehrig and the junky one to Ruth. But Babe got a cameo as himself in Pride of the Yankees and stole the picture. Babe always livened up wherever he was. Bendix as Ruth. Outrage.
Cagney would only eat there if he was making a movie nearby. Well there was that strange one in 1949, White Heat or something like that where he was a hoodlum close to mom. Some scenes filmed near Long Beach/L.A. Harbor area.
I doubt Stanwyck would be seen anywhere near there, nor would George Saunders ("G"?)
"H" might be Veronica Lake like someone said; hair is right, but she had a few imitators
"L" looks like young Princess Elisabeth, future queen. That would be quite a scoop if she was there.
Next to future Queen Elisabeth, "M" kind of looks like Paul Lynde of Bye Bye Birdie and Hollywood Squares, always in the center square with the hilarious quips. Everybody's favorite on that popular 1960s /'70s game show.
"B" looks like young Betty White. She was starting out about then. Rest in peace Betty/Sue Ann Nivens