Definitely not real cars. The one in the foreground is a loose approximation of a Chevy Vega funny car and seems to be heavily inspired by Jungle Jim Liberman's car. The one in the background is more stylized, has some Mopar influences but nothing specific.
No clue if the couple are based on real people. The artists had fun with this one, there are some subtle "R-rated" hijinks going on in the crowd.