useless trivia: What Word Means: A Twin - A Hinge - A Ring Of Two Separable Hoops?

Questions

In a popular duet, Bowie sang this while Bing Crosby sang "Little Drummer Boy"?

David Bowie teamed with he Sons of Soupy Sales & formed this band?

David Cassidy starred on tv with what singing family?

David Clayton Thomas wrote the words to this Blood, Sweat & Tears song.?

Dawn Robinson, Terry Ellis, Cindy Herron, and Maxine Jones are this group?