The song "Hair" from the Broadway musical Hair was also recorded by the Cowsills, a family group much like the Partridge Family of TV sitcom fame. Since I didn't manage to forget this, maybe you can find it in the 25 cent bins at your local used record store. Please destroy it after listening. Those were not consistently the days. "Aquarius/Let the Sun Shine In" was recorded by the Fifth Dimension. "Good Morning Starshine", with the memorable lyrics "gliddy gloop gloopy, nibby nobby nooby, na na na no no" was recorded by (I believe) Gilbert O'Sullivan. The composers of all of this were the Ragni brothers. As a film, it was the first well-known hit (not to be redundant too much) by the great (seriously) Czech film director Milos Forman.

Hope this helps. Chet W.