, thanks for your questions.
CO1 and CR1 are both logical disjuncts with three possibilities, one of which must be true -- or the assumption itself is false. So you can think of them as lists of possibilities, as you suggest, but they also purport to be exhaustive of the possibility space they describe.
CO2 and CR2 are both negations of one of the possibilities in CO1 and CR1, respectively. However, insofar as the logical structure of the NGA is presented, there's no logical path from CO1 to CO2 or from CR1 to CR2. They are each assumptions, for which we may make independent arguments.
An independent argument for CO2 may take the form of an appeal to historical trends in destructive capacity and projecting them into the future. If persuaded that destructive capacity has been increasing both in magnitude and in decentralization then, barring an argument for some factor that may change the trend, it's reasonable to suppose destructive capacity in the future will be even greater in magnitude and decentralization.
The assumption for which the most argumentation has been done directly is probably CR1 in the form of the Simulation Argument, which can then be generalized for all feasible creation mechanisms (computation or otherwise) into CR1.
Indirectly, though, we can find a lot of argumentation that relates to the other assumptions in Game Theory, the work of Steven Pinker on the history of violence, and research into the possibility space of superintelligence.
On the New God Argument website, I'm collecting information that relates to support for each of the assumptions. For example, on the Compassion Argument page, there's a list of links below both CO1 and CO2.