In one respect, methinks many might be reading something into these ads that was not intended at the time they were published. Different sensitivities for different times. FWIW
Vehicles oriented more toward the "youth market" of the earlier 1960s usually had such people in the background having fun at the beach or similar. In the case of Imperial, that was not their target market, going for something more upscale and refined. Look at their print ads from the later 1950s, for example.
Cadillacs were marketed toward females with money. In one 1955 Cadillac print ad, the title is something like "A Lady and her Cadillac", with the ballroom gown-clad lady lying across the lh front corner of the hood, as if to hug the car, smiling like she is in love with it. Or a male and female couple were dressed up very nicely, arriving at a high-class restaurant or similar venue. Pontiacs usually had younger male and females, in more "youthful" and exciting places they were arriving at or leaving. Buicks also had male and female couples, but aiming more toward "young grand-parents" age, enjoying their freedom and financial well-being as they drove through the countryside in their Buick. Chevrolet was about "entry level mobility" for all kinds of people doing all kinds of things, smiling. Oldsmobile also headed toward "youthful actions" of middle-aged male and female couples, enjoying the life they had worked years to attain.
ALL the while claiming the particular brand of car was the buyer's best choice of automobile.
Enjoy!
CBODY67