Had a similar pro bono assignment for a school overseas. Used a full frame with 35mm and 50mm lenses. The 35mm was very useful for putting context to the pictured and for candid shots of students doing experiments or teachers supervising students cleaning the grounds. The fast 50mm allowed me to do closer indoor shots with subject isolation to highlight what a student or teacher was doing.
Glad I wasn't asked to take photos of kids doing sports in the oval. I didn't have any telephoto that day.
There might be a retired concert photographer out there who could be your mentor. Sounds like a long shot but you never know how the stars could align to your favour.
Shortly after I got serious with my hobby as a landscape photographer, I happened to buy some used gear from someone who turned out to be a retired arts professor and professional photographer. He was passionate about teaching and didn't mind taking me under his wings. We met for coffee and donuts over several months. He was generous in sharing tips and tricks of the trade, including where to find the best but obscure scenic spots in our part of the country.
Secret to getting great shots often? Take pictures often. Life's law of averages says increasing attempts at getting great pictures, you will eventually achieve success more regularly. In other words, there's ni substitute for going out, taking pictures, and evaluating one's work. Repeat the cycle.