I think there is tremendous misunderstanding of what was going on in the six weeks between Lincoln's inauguration and the fall of Sumter.
During this period the CSA consisted of just seven states. Davis and its other leaders, not being idiots, were perfectly well aware the CSA was too small to be viable, particularly if it came to war. They desperately needed to grab off some of the Upper South and Border states. The more they got the better their chance of survival.
So the six weeks basically consisted of the highest stakes poker game in US history between Davis and Lincoln.
If the CSA acquired all the 7/8 states in play, the job of reconquest would have been too big for the remaining states of the Union, as Lincoln later admitted.
If the Union kept the loyalty of all remaining slave states, the CSA would collapse pretty quickly in the event of war. Just much too small a white population.
As it turned out, of course, the CSA grabbed 4 of the states in play, and the Union retained 4, or 5 if you count WV. As a result the forces were balanced evenly enough that we had a long bloody war instead of a short, decisive one.
For much of this period many in the North believed in what turned out to be pretty much an illusion of the strength of southern Unionism. In a time before opinion polls these kinds of mistakes were easy to make.
Lincoln outplayed Davis, bluffing him into firing the first shot. Doing so rallied the Upper South to the CSA, but alienated the Border (which initially tried to be neutral but eventually went with the Union), and rallied the North to the Union.
Thanks, I agree with everything you posted, except this notion that Lincoln somehow "tricked" Davis into firing the first shots.
In reality, the Confederacy was eager for a confrontation -- in my words "cruisin' for a bruisin" -- precisely because that is what secessionists, especially in Virginia, needed to satisfy Virginia's ratification statement requirement for:
Without some serious incident which secessionists could label "injury or oppression", Unionists still dominated at the Virginia secession conference in Richmond.
That's what motivated Jefferson Davis, not some "trickery" by Abraham Lincoln.
There is a fascinating account of Virginia's change from Unionist to Secessionist in Nelson Lankford's 2007 book, "Cry Havoc, the Crooked Road to Civil War, 1861."