Re 13.
If the South won independence, they would have had the west, NM, AZ and Maybe even SoCal to expand.
And they probably would have expanded South as well, taking over Mexico.
Who knows what Mexico and South America would be like today
Well, Ironically, Southern Democrat President James Buchanan *did* invade Mexico, and installed a puppet, anti-clerical regime in 1860. The French then invaded, but after Lincoln was killed, Southern Democrat Andrew Johnson invaded and set up another even more anti-clerical state in 1865. Sentiments on both sides of the Civil War were so high in favor of the anti-clerical Mexican state that the Hampton Roads peace conference actually discussed a Confederate-Union alliance to invade Mexico.
U.S. interests also supported the Trotskyite Mexican Revolution (1910-1918), until their puppet Pancho Villa outraged Wm Hearst by attacking New Mexico.