Here's the finished product. After scrubbing all the seats and applying leather preservative, my son and I spent the afternoon reinstalling it all. The car actually smells nice now. No more smoke residue.
I was able to salvage the cracked polypropylene seat bolster by using the plastic welder and extra polypropylene welding rods. The repair is underneath and on the back side so it is invisible unless you remove the seats.
I also used some flexible bumper repair material, supported by wire mesh, along with a couple zip-ties, to the pull the two large cracks together on the driver's door panel and then permanently repair the cracks. There is still a visible repair spot but not nearly as visible as the original 1/16" fractures.
We pulled the passenger side panel to reconnoiter the condition and found one tiny crack about to start in the same locations - the 90 degree angles that are cut into the panel where the inner weatherstrip attaches. We removed the factory staples, reinstalled new staples in a non-stressed locations and then used the flexible bumper repair material to form a layer of internal bracing to the area.
All is well now, until we can find a nice unbroken (and inexpensive) driver's side panel.
