Thank you, you're right, I shouldn't engage in "what if" scenarios.
However, regarding the second question. If I kissed the outside of her vagina a couple of times, her inner thighs too, and she had rubbed herself against myself a couple of times, can I safely assume no risk, and go on about my life?
Or would it be reasonable to test? This will be my last question, unless someone asks for clarification or further information, I promise. Thank you!
You can't make up a risk where there was none to begin with. So your one in a million question is totally irrelevant. Neither of the scenarios you posted result in HIV infection, so you're wasting your time testing for a disease that you can't possibly have. If you find yourself frequently testing for diseases that you were never exposed to then you really need to find a therapist to discuss your irrational health anxiety. It's not normal behavior and it requires intervention from a professional in order to overcome this type of mental problem.