I do not think that the plan would have worked without Cyrus. There was something special about him that appealed to the other gangs. Presumably even enemies of the Riffs signed on to the truce because of Cyrus's reputation. Heck, almost everyone at the meeting seemed to like his idea (cowboy especially).
Now, for whether his plan was viable. I think people are taking out of context what he had in mind. People talk about calling in the National Guard to put down a riot. I do not think that Cyrus had some sort of riot planned. From what I understood, he seemed interested in collecting fees and taxes from the crime syndicates and the police for moving through their territory. Certainly this would be something that higher law enforcement would need to become involved with, but not the National Guard. They do not use the Guard just to fight street crime.
Cyrus Plan
Re: Cyrus Plan
In our society, or should I say our entire human existence there have always been cases like these. Jesus sacraficed himself for his people. Dr. Martin Luther King Jr was killed after he touched the heart of millions. Cyrus was like a modern day prophet. His glow, his essence, his enlightenment, hypnotized, and altered the way we think about life. Now I don't know if he really was a con-man, or someone who fealt the touch of God, but there is always catch. He died leaving people with a new look on life. Now its up to them to see how their destiny will form or what path in life they choose. My point is, I never really think about how his plane would have worked. Its more of how will we use his teachings to find our selves in a complicated universe. So just like Dr. King or Jesus, it like they were meant to die, to see how we place ourselves in society, after hearing their teachings. I don't think about the "what if they lived" . I think of how ill society function without them.