Who is Wenner Zergog, Lido Mamin, Tab Jones, Mack Derouac, Jon-Luc from Hollywood: A Novel and what is their importance?

Bukowski mentions characters throughout the novel, who are based upon real-life individuals. For the most part, they are referred to glancingly, but with a vividness of description and establishment of context that defines them. These characters are based on Werner Herzog, Idi Amin, Tom Jones, Jack Kerouac, Jean-Luc Godard, Jean-Paul Sartre, Norman Mailer, Sean Penn, Madonna, and Taylor Hackford.