I'm interested in a system that allows a John Stuart Mill and an Anton LaVey to peacefully coexist without attempting to judge who is more 'objectively' moral. I wish to be able to choose my own terminal values without having to perfectly align them with every other agent. Morality and ethics are then the minimal framework of agreed rules that allows us all to pursue our own ends without all 'defecting' (the prisoner's dilemma is too simple to be a really representative model but is a useful analogy).

You're talking about 'politics', not 'ethics'. Politics is about working together, ethics is about what one has most reason to do or want. What the political rules should say and what I should do are not necessarily going to give me the same answers.