I can't do any more than sympathise over your electrical head scratching. I had the same sort of problems a few days ago adding the aircon engine and compressor wiring from a '96 Discovery to my soft dash RRC - while the hardware is the same, the Discovery wiring was different as it was changed in 96. Thankful;ly, I have a mechanic friend who is used to the LR "electrical troubleshooting manuals" for the 95 RRC and the 96 Discovery that I was able to borrow from my local specialist.
Taking the dash out was more un-nerving to me than rebuilding engines or transmissions. Now I feel comfortable in my desire to do a full rebuild, though without any more mods. I think I'll copy your use of Lizzard Skin on the interior of the shell, once it has been blasted, repaired and hot zinc sprayed. Still, all of that is years away - I'm going to have to save long and hard first.
Great to see more progress on yours, though.