Got the base plate in, and the smaller plate. I only cut exactly 1.5" off the bottom of the studs, so it was a bitch to get that in under the studs. The large sledge helped.
Under foam barrier & butyl
Funky piece to fit the corner. Had to shave 1/4 off the whole piece to clear the existing concrete, then used the router to cut a step that tucks under the cross plate, as did the original
After that was fitted, I added an extension to the 2x4 plate, then a 7" section of 4x4 to repair the corner post, then a similar length for the visible stud that abuts it.
New siding for the 3rd run, Concrete backer for the lower 10"
Covered with Protecto-wrap, this stuff sticks to anything.
Now I can put up the last pegboard, move everything back , and get moving on the V8 conversion for my Volvo truck.