I'm sure you got a lot of ideas here. :-)
Each of us are from different schools and our church situations and talent base varies. I have been privileged to work with mostly white or mixed choirs and grew up in Mississippi with just good ol' black church folks.
When I go back into "black" church situation to teach workshops or clinics, most are not readers at all; I teach them by rote and continually have them sing. In other words, I use short phrases in a song and I start with whoever has melody and let that section sing their part as I add the others to it. If there is a bass section, I teach them after the melody is taught, then add the harmonies beginning with the most difficult.
When I work with my church choir things are different. I never let them hear a song until after I have taught it because many times, I change lyrics to fit our Theological or cultural understanding and I don't want to confuse anyone on words. Also, I often arrange parts differently or even completely rework the chords and vocal movements; I only let them hear a song to get the "feel" of it.
I do have my praise singers in microphones at all times because they learn quickly and help me coach the others. I do not have them learn ahead of time, because I don't want people in my praise team to ever feel elitist or get "special" time with me that others don't get. That's something personal for me.
I do give my choir a minimum of three weeks before we sing a song in church, so by the time we perform it in service, they really know it. I don't believe in teaching a song Thursday night and us sing it on Sunday, unless it is so repetitious like Dorinda Clark-Cole's "I'm Determined." Very few of those songs are written in more. LOL
Send a private message if you want to discuss this in detail with me.
Pastor Forster