This last one caused me a bit of head-scratching. I started with the car, which I thought I recognised, as my puzzle #3 back in 2010 was a Scampolo single-seater racing car, and Heroes 7 shows three of them. I think Walter Komossa, who was involved in designing and building them, is the driver of the car in the left foreground. I don't know who the other driver is.
There have been several films called "Scampolo" over the years, with at least two from the right sort of period. However, I think it's the 1928 film with Carmen Boni in the title role, and I think she is shown in Heroes D.
The car in all the pictures is the Peugeot 12CV Six, current from about 1927 to 1932. It came as Types 183 and 184, but I'm not sure you can tell them apart, as I think only the engines were different.
The series of postcards has on the back "Collection Peugeot - La 12 Six et les Célébrités Contemporaines".