I think it's not really possible to discuss them in a vacuum, as they are defined primarily by exclusion from others. I understand the apprehension of a chaotic mess occurring, but I am optimistic that this will not be the case, and if it is we can always create new threads to funnel the discussion into more clearly defined categories by making new threads, so I wouldn't worry.
To speak more specifically, I am only aware of Ultima's contention of leaving Morrison and Snyder/Tynion as a single cosmology, which I am somewhat open to depending on how we define this cosmology. I don't know of anyone that objects -- specifically -- to a "Vertigo Cosmology" or a "DeMatteis Cosmology" and the argument for another distinct "Williamson Cosmology" is getting clearer by the day. So I think we can move forward with a single thread that discusses all of them, and if/when the need arises, we can create a separate thread for the Snyder/Morrison issue so it can be discussed without making the main thread a mess to read.