No it doesnt. Pregnancy only happens when sperm reaches the egg through the vagina. There's no connection between the mouth/stomach and the reproductive system. So relax on that part.
Short answer no. For pregnancy the sperm has to reach the egg through vaginal intercourse. Oral contact doesnt do that. If u still have doubts or worries about anything, a gynac can clear it properly.
I had similar confusion when i was newly married and too shy to ask anyone. But no, it doesnt cause pregnancy. These doubts are normal, please dont feel embarrassed about asking.
Nope, not possible that way. Pregnancy needs sperm to enter the vagina and reach the egg. Whatever goes in the mouth goes to the stomach, completely different system. Dont worry about this.