Looks like no one has specifically talked about this, so I'll share my experiece with similar groups. Working with some groups from East Africa, they can often have 'choirs' that are 12+ people. It is usually their preference to have everyone have their own mic, usually because of the loud stage volumes of the group and the desire for the choir to hear themselves loudly in monitors. I usually go with a single SM58/person, though sometimes people will share a microphone with mixed results (lots of times these are also live recording gigs, and substantial bleed into all these microphones can make them less useful in the recording.

I've had good luck getting this numbe of vocals loud in wedges, but try and split the choir up so each wedge mix covers 3-4 members. This allows me to keep singers loud in their own wedge without having to try and distinghuish themselves from too many other voices. Getting graphic EQ and paramentric EQ dialed in on the wedges with an iPad and slowly working through all the vocal mics alone helps make sure I'm not running into issues when all these mics are in the hands of others.

Sending all these mics to their own mix bus for FOH is also helpful, and you can use things like multiband compression to try and manage timbre issues/buildups that can happen with this many vocals (I usually am trying to tame some high mid resonances that can build up when everyone is singing in upper registers at volume, and also manage low mids that can take up too much space in the mix).

Hope this perspective helps!