can you tell me if this question and answer are correct:

Question

1. Est-ce qu'il te faut un stylo?
Ans: Oui, il m'en faut un

Answer 1

I am probably wrong, but I would have asked:
"Est-ce que tu as besoin d'un stylo"?

Answer 2

Answer:
"Oui,j'en ai besoin"
At least, that's the way I would say it.

Answer 3

It's also a good question: Are you lacking = do you need = Est-ce qu'il te faut un stylo? Oui, il m'en faut un.

falloir = an impersonal verb meaning "to be necessary"

Sra (aka Mme)

P.S. You are both right!