I’m a guitar player and singer. Is it okay to join an interfaith rock band? If I were actively involved, the lineup would be the following: a Catholic (me), a Buddhist, an atheist, and a Wiccan. The band would not necessarily be religious in nature. I (the Catholic) would be writing the lyrics. Any thoughts?
The main problem with rock bands is not participating in the band but avoiding the problematic lifestyle often associated with it. If you are strong enough in your faith to avoid the immoral situations that may be part and parcel with performing onstage, playing in clubs, and perhaps, if you become successful, touring, then there is nothing intrinsically sinful about playing music and singing with non-Catholics.
In your case, as you will be responsible for the lyrics, you, as a Catholic, will not write songs that glorify immorality. Were someone else to consider joining a band and he were not responsible for the lyrics, he would have to consider more carefully if his input in the music were influential enough to prevent being expected to participate in performing morally problematic songs.