Hmm… well, I am sort of a newish Catholic, and I am still learning here, but aren’t choir members part of a lay ministry? Just like Eucharistic, stewardship, Steven’s, etc… Seems that the lay ministers do have a greater responsibility to remain in a state of grace, meaning frequent confession, greater participation in daily Mass, etc, since they have to deal with greater challenges, potentially in the form of spiritual warfare.
I once served in a choir for about a year after my confirmation, and there was an expectation to watch over each other’s spiritual health and well-being. I am not sure if that is the norm in Catholic choirs, but I would argue this is necessary to fulfill Christ’s desire for unity, and I really believe the lay ministers need to serve as role models for this unity effort.