Maybe. It still must be hit on the sweet spot between the toe and heel.
Probably. The Pendulum Putting Rod makes it very hard to miss the toe/heel sweet spot.
All of the above.
Pay attention to hitting the ball in the equator.
Pay attention to keeping consistent posture.
Relax. The putter will swing itself.
Focus on the target.
Yes. It is the center line of the ball.
Yes. It is the equator of the ball
Yes, it is the intersection of the equator and center line
Bounce the ball on the sweet spot of the face.
Hit some putts extremely high and low on the face to demonstrate the feel of a mis-hit.
Hit several putts. Ask the student if each felt solid. Note the distance the ball rolled. Sweet spot putts roll further.
Use A, B, and C to teach the "sweet spot" feel.