it worked!
I bought another level. The floor is exactly level, not even off by half a bubble. At the door at least which is all I'm trying to fix now. The walls leaned but not as much as a few days ago when I last posted. So evidently they were still adjusting.
We drilled, then screwed in anchors. Then ratcheted it tight. It moved enough for the strap to get a little slack within an hour or so. We pulled a couple more clicks and the walls are straight and 90 degrees to the floor.
The doors now fit into the door frame, the top hook works easily, the latch fits perfectly. Only the bottom bolt doesn't quite fit - it is off by half the bolt rather than way off.
I fitted one diagonal in before dark. The rest will wait because there is no electricity in the building. It will be a lot easier in daylight.
That's terrific!