20. I'm not City Van Zandt or County Van Zandt.

Hoyt Axton?

Oh for gosh sakes. I just let your last clue hit me: Townes Van Zandt. LOL.

Excellent!

Never heard of him.

My very next guess was going to be "Somebody I never heard of before?"

As always Landmark is one step in front of me again!

I can't recommend him highly enough. He is without a doubt in my top five songwriters. Maybe top three.
I think this recording is POWERFUL:

https://youtu.be/v-Rq-4spRz4

In the late 60s and early 70s I used to listen to a freeform FM station (WBAI NYC--where I work today!) and there was a guy with a late night show who always used to talk up TVZ.

1. My dad was a minister.
2. I was heavily involved in the anti-war and civil rights movements of the 60s.
3. I was a Conscientious Objector to the Vietnam War--probably the first in my county.

4. The bad news is that my attempts to follow in my Dad's footsteps failed.

5. The good news is that someone at the seminary set me free to follow my true path.

Timothy Leary?

I have no idea ... but since Cliff guessed Timothy Leary, I'll venture: Ken Kesey?

Not Tim or Ken.

6. It turns out that my calling was performing.

7. So I showed them my stuff on the streets of New York and then I travelled to California.

Harry Anderson?

P.T. Barnum?

Not Harry (a good guess though!) or PT.

8. Billy, my mentor, suggested I change my last name to something more pronounceable, so I did, though it's not too different.

9. I performed at one particular West Coast venue many times, and for a while I was Vice-President of the organization.

10. Three must be my lucky number, because I even wrote two books about doing things with three objects.

11. I had a mid-life renovation where I changed my performing style quite successfully.

12. I'm full of surprises--especially my opener.

13. Pixie dust?--no problem; I grind 'em myself.

Whit Haydn?

You got it! Whit Haydn, whose name was Hadden before Billy McComb told him to change it, was the VP at The Magic Castle for four years. Fortunately for us, his superiors at the seminary told him he would best be serving God by using his magic talents rather than becoming ordained.

He almost always opens his set with his version of the Chicago Opener, "Chicago Surprise."

And he self-grinds his own pixies to ensure the purity of the dust.

Nice one, Landmark! And good guess, Critter!