JCP and Sears published two big book catalogs every year. One in the spring and the other in the fall. Getting these was always a big deal. There was no internet then and these catalogs represented a connection to what was happening in fashion for the average household.
The first photo is from the JCP fall winter catalog in 1971. This is about as early a catalog photo of Kathy as I have been able to find.
Kay Campbell is to Kathy's left. The other model is unknown. I'm not sure why you would want a leotard with a turtleneck. Seems to me that it would be pretty hot but I guess the idea is that you wear a skirt over it (from the insert pic). That way you can go to the gym straight away from work, rip off the skirt and jump into the aerobics class. Also that combo doesn't seem real practical to me to wear all day (how do you go to the bathroom)?
The next two pics are from 1976