Thanks for the backstory on how The Partridge Family came to be. I had heard before about the show being based on the real life Cowsills but didn't realize they were actually planning to cast some of them. Makes perfect sense that a studio band backed Shirley Jones and David Cassidy for the recordings. It was obvious by watching the show that the rest of them had zero musical ability.
Cowsills are an overlooked band in my opinion. Many of their songs still hold up well today.