You're more likely to see worn rear coils than front torsion bars. The weight on the front end tends to be more static. The coils are kinda known for being a little on the soft side. I just replaced a set for a customer that had sagged almost two inches.
Any dealer here in the US can get them. Most will tell you it isn't available because it has been supersceded. However, Toyota's main warehouse in Ontario, CA stocks them. Your local dealer may not want to sell you less than a case though.
Starting next week, I should have a few cases as well.
Don't worry about embedding the brake pads into a hot rotor. The bigger concern when bedding in new pads is to not let the rotors get super heated and then come to a stop, as this could cause the rotors to warp.
BTW, good luck getting NAPA to cover rotor warpage under warranty. Some will...
I admire what you have accomplished in such a tight spot! My only concern would be the longevity of the plywood, due to its enviroment. Motorhome builders used to use marine plywood in the construction of RV's. However, the elements would eventually take their toll.