Dear Ken,
I find your axiomatic approach interesting (it reminded me a bit of the approach presented in Richard Shoup's paper).
I did not follow your entire derivation but there are two issues I would like to point out in the spirit of constructive criticism. First, it seems that you would like to derive the introduction of additional coordinate degrees from your original axioms, but I'm not sure that is possible. For example, you may wish to check with a mathematician, but it seems to me that the step
"The only way to satisfy the axioms is to expand the
coordinate system to include a second degree of
freedom.(p3)"
Amounts to an additional unstated axiom (namely, that there is a second degree of freedom). The problem, as I see it, is that without it all you have is an inconsistent system. If this is right, it should still not be a big problem to fix by adding it to your initial set of axioms because, as assumptions go, that is a rather harmless one (this also applies to the Z-dimension).
Second, it is not apparent to me how you arrived at equation 4, which applies to a continuous manifold, given that you apparently started with a discrete geometry. In fact, I got lost right at the first sentence of section 3.4. Perhaps a picture might help, but fundamentally I didn't understand how curvature suddenly entered into the discussion. Even if I take it as a given that curvature did enter the picture, it is still not clear to me how you get to equation 4. One can certainly define curvature for discrete surfaces, but as I understand it, then integrals become sums and differentials become differences. My understanding is that the Ricci tensor and Ricci scalar are defined (at least in their standard form) only for continuous geometries. So it seems at least a possibility that somewhere an extra assumption has crept in by which the discrete geometry has turned into a continuous one.
If that is true, then I would deem it a much more serious hidden assumption because it changes the entire character of your approach.
In any event, as I mentioned your approach is interesting, but I would recommend that you check with a mathematician on the validity of some of your steps. I hope you found my criticism useful.
Best wishes,
Armin