It is kind of interesting how long it took for people to start applying distortion to other parts of the track outside the guitar. Seemed like that started when people were doing 4 track mixing on little cassette tascoms that would clip unlike expensive studio multitrack setups. Neutral Milk Hotel and such.

As far as vocals go, I think it didn't take people long. I think overdriving the microphone mixer is probably as old as the recorded blues. There are swing recordings from the 1930's in which loud vocal passages distort. I don't have any specific references, but I'm sure it's something I've heard before.