When I fly with someone else's student, I often find myself suggesting different ways of doing things. I always try to point out (at the time if appropriate, or else in the debrief) that my way isn't necessarilly better than the other way, it's just a different way..... the student, being an intelligent human being, can listen to my reasons, listen to other instructors' reasons, and make up his own mind which method suits him best.
Not sure how well this would work with your student, who sounds (from your description) to be obstinate, and who also appears to be plain wrong in both your examples. But it might seem less confrontational than simply telling him that he's plain wrong?
If that doesn't work, you could try the other extreme, and be more confrontational. When he is captain, he can run the flight the way he likes, but since you are captain for this flight, the flight will be done your way, and that includes using checklists and turning the landing light off whenever stationary.
Please let us know how this turns out - I'm interested!
FFF
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