Hubley...great topic and points but I doubt anyone who performs a 'resurrection' on a car would want to call it that...perhaps the term would be more useful to describe a known vehicle by others in the hobby, kind've like a frankenstein thing?.
As usual, until your own or trusted eyes can view something and decide what's really there, anyone's description will forever have to be considered as a 'beauty in the eye of the beholder' kind've thing ?.
On the Shelby GT500 you've described...using Bloomington's base Survivor criteria, this car would actually not be able to attain the designation as with both paint and motor being more than 50% changed it would fail to meet the 'three of four' rule..
The thing I see possible slipping through the Survivor process is the saving of survivor parts and installing them on a vehicle they were not originally shipped on?.
Picture a nice original engine car with racing seats and a big scoop added to the hood years back but still retaining mostly original paint otherwise...swap in correct original seats and a correct original paint hood in the same color...if the paint tone was correct and nobody knew the car previously, you could then pass the interior and 50% original paint part and you're in?.
~ Pete