Hey, @Aggroed. Interesting concept that you've laid out here.
"The idea is that all individuals are free to live as they want as long as they cause no harm or threat of harm to another individual or their property."
I think this is a pretty good starting point for any kind of discussion surrounding the ideal of peace. The tricky part emerges when we decide what constitutes "harm" or "threat of harm" to another individual and their property. I imagine you and others you've discussed this with are already aware of how difficult that can be to discern.
For example, if I am free to engage in economic enterprise without any limitations on my freedom, I could harm other people in doing so (through environmental damage, soaking up too many of the economic opportunities for one's self, etc.). However, there would be some camps that argue that it would be unreasonable to place restrictions on anyone's economic activity.
I'm on board with the non-aggression principle, but I get a little lost in what constitutes aggression and harm in the first place. You pointed out the biggies like murder and theft, and of course that makes sense. I think once we step into the gray area, it gets murky pretty quick.
But hey, this isn't about absolutely air-tight solutions, right?