Just returned from Connooga, a multi-genre convention in Chattanooga, where my new novel Pricness Pain was released. This novel was adapted from my script of the same name and I had several interesting discussions with indie producers about the value of having a novel to back up the script. I've heard this from other producers in Hollywood as well. It's not a requirement but its nice to know that it can add to a script's marketability.
It can indeed, but only if the book has a level of success. Good luck.
So true. Book sales are a challenging business to start with. Once past that, it does offer an opportunity for a producer to understand what goes on behind the script. This might embolden a producer to embrace the script or suggest a rewerite based on other ideas of the concept.