Who is Jocelyn and Rhea from A Visit from the Goon Squad and what is their importance?

Jocelyn and Rhea are two of the members of Bennie's San Francisco band. Jocelyn is the first to meet Lou who she believes to be her boyfriend. Jocelyn and Rhea are childhood friends that are inseparable initially. At the age of 43, the girls meet up at Lou's to say their final goodbyes.