Wow, what great research on your part to answer the question I had posed. One reaction I have to this is that it goes to show what a mess resulted from confusion over geographical boundaries with the opening of Kansas Territory. The future prosperity of individual settlers was often in the hands of those who would settle boundary disputes, which abounded given that settlement was allowed before the land was surveyed. When the elected government was declared "bogus" and a competing free-state government was set up, one result was a dispute over what entity would resolve the boundary disputes. Accordingly, disputes over claim boundaries got caught up in the slave vs free dispute. Settler who didn't feel strongly about the slavery issue were motivated in the extreme in getting claim disputes settled in their favor, which led to their alignment with and support (sometimes involving militant support) of one or the other of the competing governments. Therefore, I conclude the Border War was to a significant extent about land, not slavery.
I would very much appreciate your take on this subject.