You can write this down in your applications to universities. These are very good ECs. This shows responsible behavior and a willingness to help others. You have also shown a long term commitment to violin, three year commitment to track and field, and I am guessing that you have multiple years of taekwondo if you are teaching it.
To me these look like very good ECs. ECs do not need to be academic in nature, and do not need to be through your school. Having ECs that are not through your school show a willingness to be creative and thoughtful in terms of coming up with other ideas. Also, having ECs through a church is relatively common.
Just these words as is are very good.
My take on having a “dream school” might be summarized by my experience applying to graduate programs. I was turned down by my “dream school” graduate program. I went to my second choice. I LOVED IT! My second choice had always been a better fit for me. I just didn’t realize this until long after they handed me a master’s degree. Admissions at both universities got it right (including the “dream school” that turned me down). You have great grades and great ECs. I am betting that you will probably get great references. It will work out one way or another. Whether it will be at WUSTL or somewhere else none of us can predict.