License plate placement.
The rules are actually quite simple. The 'numbers' must be exposed to the air (so not behind the windshield) and be at least 12 inches off the ground, and not more than 60 inches off the ground. Other than that, any placement on the front or back license plate appears to be legal. So my intended plan of replacing the 'C I V I C' emblem-plate on the back with my new rear license plate is legal, as is my plan to replace the front 'H' emblem on the hood-latch bar with my front license plate.
Obstructions of view in the windows.
These rules are, also, quite straightforward. Section 26708(b)(8) expempts all the glass rear of the front seats once I get both side rear-view mirrors installed. Once I do that, I can get the rear side-windows removed, welded over with sheet-metal, and fold-down shelves installed into the sheetmetal as planned. For the rear, I'm doing something a little more daring. The glass also goes away, and will be replaced with a sheet-metal panel with the fold-down shelf as well. The difference will be that the shelf will be have a section built from a very strong metal mesh, so I can see through it with a reduced-size rear-view mirror without incurring the wrath of having non-safety glazing material installed into the vehicle.
Odometer repair exemptions.
This section makes my life SO much easier. I can legally remove the existing odometer to replace it with another one, so long as I affix a plaque like the 'VIN' plaque reading the original milage, and date of milage originally taken, and can set the new odometer to 0. Why I want to do this is actually for a different reason than most think. It's the thing I want to do when the vehicle is done being modified, to signify the 'rebirth' of it fully into it's new life.