You're a brave man, Brother Fielding. Since I was a teacher (yes, it was a one room school house), I think instead of singing protest songs to them, I would make it a workshop where I sang some examples and broke down the techniques used to protest: metaphors, analogies, narrative, symbolism, etc. and then help them to write a collective protest song. Use THEIR ideas. If they are creating they will be engaged. Sorry if I'm too late with suggestions.

Good luck, Chance.