Can pre cum cause pregnancy after crossing 2 layers clothes?

Maybe/not. All semen have some sperm. All sperm are fragile, dying quickly if they leave the protective moist environment they prefer and enter an environment that is dry. If you can come up with a way they can penetrate clothing layers without drying out it might be possible. I don't see it happening.

Same question, same answer... In the scenario you described, pregnancy is not in the cards. It appears that you and your partner are moving in the direction of actual intercourse. It would be wise to learn about appropriate contraception. Here is some information regarding how one becomes pregnant: https://www.plannedparenthood.org/learn/pregnancy