There is a difference in being pitch challenged and tone deafness. From what I can tell, you guys are not dealing with tone deafness, which is when hearing loss causes one to not be able to distinquish any one tone from another. They tend to sing monotoned or randomly go up or down without knowledge. You hit the C note and they sing F#. You play A, they sing F#. That is tone deafness. I deal with these people by asking them to serve as copiest, making tapes or cds for the choir members. I have them work with me as administrative type people, which still keeps them connected to the ministry without them killiing ministry. I allow them to sing with choir, but only on the back rows far from microphones. But this also allows them easy access to slip out if I need something from the choir room or office. It truly is a win-win. I spend time talking with them so they don't feel like a stepchild.