ahahaha I laughed at this
1. Sports, aesthetic, mechanical, and theatrical ability are the examples of Se function, but there are other Se functions as well. Just because someone is good at these kind of Se function, doesn't mean their MBTI type is xSxP. It's all about what is dominant. An ENTP could have done better in all Se things mentioned above, but if he uses Ne more often, he is an ENTP. An ESTP could be a master of improvising something, but since he uses his Se more often, he couldn't be ENTP.
2. What distinguish Ne from Se is how they process information to be impulse to act. It's all about which route do you drive, not which type of ride do you drive. A Se author writes using his/her experience and the way he/she sees life, and it will be different POV from a Ne writer. Also a Ne martial arts guru could have done it because he actually learns it, curious about it, not naturally does it like Se guru.
All these stereotype (ESTPs are meant to be like Tom Cruise, INTPs are like Einstein, ISTPs can fix car) are meant to be jokes anyway. I have a friend who is ENFP and her creativity is terrible, my ESFP friend has better imagination than her. But the way ESFP tells her imagination is different from the way Ne tell their imagination.
That's why we have an ESTP author (Ernest Hemingway) and INFP action movie actor (Johnny Depp)