tv/ movies: Category: Entertainment Grabbag: He played John-Boy on The Waltons?

Questions

what singer performed on the santana hit single, smooth?

what singer starred on radios "your hit parade"?

what singer was in a car crash with sam cooke & mistakenly pronounced dead?

what singer/guitar player opened for the monkees during his first u.s.tour?

What singer/songwriter was the inspiration for neil sedaka's oh carol?