RE: Spanwise Lift and Stall Sequence
If you want to see what goes on during the stall of a wing just go to youtube and search for "RV-12 stall tests. There you can see a wing that has been tufted for the test and the reverse flow that shows where and when the airfoil of the wing is stalling.
On a rectangular wing, the stall is a gradual thing, starting at the trailing edge at the root and working forward and outward as the stall is deepen.