Is it possible to get pregnant if a penis comes in contact with a vagina but it doesn't penetrate nor does the tip go inside? And what if the tip has pre-ejaculation and touches your vagina but doesn't go inside your vagina?

While very very slim, yes there is a very small chance

Yes, it is. Sperm can live up to 48 hours outside the vagina... And its 35% chance of getting pregnant of pre-ejaculation. I was one of those lucky ones