Good for you, i think its a great idea and i wish you guys the best of luck.
''People might be sceptical about this, and wonder what the point is of talking philosophy with the poor, the homeless, people in our criminal justice system, and disadvantaged migrant communities etc''
I think its good to engage with these groups, though more in need of an injection of ethics is the ruling class of politicians, corporate CEO's, royalty, and the vatican!
Teaching morality should be fundamental in public and private schools. Teaching criminals in the justice system should be interesting. I think that most criminals know that their actions are wrong but do them anyway because they dont care or that they need the money. On the other hand the legal system itself can be immoral, selling a medicinal plant for example does not merit ANY time behind bars. People should be free to consume whatever substance they want. if we own anything at all, we own our own bodies.
I respect your voluntary work samuel, just be careful you dont get stabbed in the neck by a psychopathic inmate!!