The height of fertility is not a teen, haha. This is a serious misconception, it is actually your twenties. With that being said, yes, pre-come can get someone pregnant at whatever point on the fertility scale.
Yes, precum is as potent as regular ***. If not, more.
Any women having unprotected sex wether pull out method or not could still get pregnant. With precum it still has a tiny bit of sperm in it.
Yes. Its possible. At the height of fertility, prec*m does have sperm in it, so it is possible.