If I read this,
from ASCAP, the rehearsals and the lessons would be exempt, but the actual competitions might not be.
2. What is a public performance?
A public performance is one that occurs either in a public place or any place where people gather (other than a small circle of a family or its social acquaintances.) A public performance is also one that is transmitted to the public; for example, radio or television broadcasts, music-on-hold, cable television, and by the internet. Generally, those who publicly perform music obtain permission from the owner of the music or his representative. However, there are a few limited exceptions, (called "exemptions") to this rule. Permission is not required for music played or sung as part of a worship service unless that service is transmitted beyond where it takes place (for example, a radio or television broadcast). Performances as part of face to face teaching activity at a non-profit educational institutions are also exempt.