I hate to be a wet blanet, but these tenuous notions for creating choirs really doesn't reach me at all.
The idea nurses, priests, soldiers, soldiers' wives and so on ad infinitum, make viable choirs is simply not valid.
What it is is an excuse to cash in on the emotion that surrounds these individuals for their various reasons, and use that as an excuse to carry through the idea that this is some sort of cathartic 'journey' for everyone involved.
It's not, it's TV cashing in on national attitudes towards these individuals, and it's basis is groundless.
A woman who marries a soldier does so from simple free choice - it does not empower her with the national goodwill that allows her to join a TV-based choir and appear full of cod emotion and self-righteousness which is the wave of emotion that fuels these ideas.
It is this kind of nationalism / emotion-by-proxy that allows national forces to carry on in their primary function - fighting wars, however unjustified.