Matt,
I believe that the unused art is just that, and doesn't indicate that anything is missing from your .txt files. It could be stuff they ran out of time to do, it could be items planned for the future, it could be so that players have new art to use for their own mods, or it could just be leftover stuff. Good work finding and describing all that (a lot of file-opening and typing
).
However, while there's one picture for each family of component, there are often several components within a family. For example, there's only one picture for Emissive Armor, but there are three Emissive Armor components: Emissive Armor I, Emissive Armor II, and Emissive Armor III (and all six Meson BLaster components share a single picture). The Roman numerals are just placed on top of the one picture. So, ~100 pictures can, and do, represent ~450 components.
As for starting with High Technology, no, that doesn't guarantee that you'll start with everything. There are still special techs that depend on racial characteristics (such as Crystallurgy for Crystalline Armor) or that must be found (such as Massive Shield Depleters). If you want to see all facilities and components, set up a new game and turn on "Players can see complete tech tree" under Game Settings. Once the game starts, they'll all appear under Research/Tech Tree/Tech Levels, with gray items being those you can't currently build. A
rough count of all the components and facilities shown there comes to
approximately 560, which matches well with results of doing a Find in the two .txt files (580). To be able to build
everything, you can create a race with those special abilities, and then find the ones that must be found.
So, you can relax. I don't think you're missing any components or facilities; I think it's just a combination of unused art and not seeing the whole tech tree that makes it appear so.
Wendell