No, those questions are not fatuous. But there are others. For discussion sake, let's say Lincoln saw fit to allow the southern states to secede, and the Confederacy become it's own nation. There could then be the possibility that the lessened Union could then vote for the repeal of that portion of the Kansas/Nebraska act that repealed the Missouri Compromise of 1820, and outlaw the issue of slavery in those states. They could also pass a law that slavery would not be allowed in any further territories or states.
What then would the South do? If they continued with slavery in their initial, few states, it would begin a fairly increasing death cycle. Their only out would be westward expansion, or expansion elsewhere (Mexico, Cuba...). But expansion within what's now the continental US would likely be opposed by a more solidified Union. Would that then make the war just as inevitable as it was in 1860?
All is conjecture. Who knows how history would have unfolded. But the issue of slavery was a cancer within this country from before its beginning. Is it possible it could have been cut out without a major upheaval of blood? To me, that's the major question.
Slavery was widely accepted throughout the world prior to the Eighteenth Century. It was in 1776 that the British High Court ruled that “slaves cannot breath English air, for the moment that they do, they are free men.” Some historians claim that it was this action, and its implications for England’s colonies, that lead the Southern colonies to find common cause with mercantile New England. (New York was notably tepid in embracing the Revolution.) In other words, the American Revolution had as much to do with perserving slavery as the principles of representative government.