The families you talk about will be facing military trained people, not street thugs, so a band of 16 ex-military folks would be a handful for untrained people, is, I think, the point OP was making.
I think the ex-military premise is wrong. Military folks have the discipline,, team skills, and intellect to be just who I would want around me in such a situation. It will be the street thugs, who are already parasites that would try something like that. They won’t last long around ex-military types.