Hello. You seem to identify the mathematical character with the presence of symmetries. I agree to see a connection between both, but not as much as you do. One way is clear : a symmetry means an exact correspondence between parts, and such an exactness is characteristic of the mathematical nature of a system. However the converse is not true: a system can be mathematical but still not symmetric.
In my essay I explained how I analyze what it means for systems to be more (remarkably) or less mathematical. The basic condition is having a simple foundation, but then simplicity may qualify more or less important aspects of the systems (may these aspects be "foundational" or not). Symmetry contributes to wide aspects of simplicity for big systems, and thus to this mathematical character.
Systems without symmetry can still be completely mathematical, they are only less remarkably so. For example, mathematical models can be extremely successful (or anyway the only available method even if moderately successful) in engineering, meteorology and astrophysics, despite the usual absence (or lack) of symmetries there. The problem with big systems without symmetries is that they are usually quite complex (because, of course, they have many elements not isomorphic to each other, thus having all different properties), which usually does not fit very well with the possibility of a complete mathematical description.
Still there are possible exceptions. For example, in my essay I pointed out a way other than the presence of symmetries, by which quantum physics is also remarkably mathematical (simple) in a wide range of aspects. Outside physics, we can also develop elegant mathematics without any symmetry, for example the theory of ordinals. We can also consider algorithmic as a branch of mathematics that does not have any symmetry in its foundation.
You seem to see physics and economics as very different fields, as concerns the kind of concepts they involve. I don't. On the contrary I see a remarkable similarity there : the fundamental theorems of welfare economics describe the conditions of market equilibrium and stability of this equilibrium, in much the same way as the equilibrium of classical mechanics. Moreover, in both physics and economics, this concept of equilibrium should ultimately be applied not to a specific instant but to whole histories, regarding time as a space dimension like others (relativistic mechanics does so with the least action principle).
Of course the problem with the economic case is that this model is only an idealization that misses more aspects of relevant phenomena than in the physics case. However the mathematical concepts of these models are remarkably similar, and also have in common to not contain any symmetries (there are many possible physical problems to be analyzed by the least action principle and not concerned by any symmetry; they can be very complex too by the choice of the systems to consider, you can find plenty of such in astrophysics and mechanical engineering).
On my side, I work to analyze economic problems and possible solutions by means of high-level, elegant mathematical concepts, such as how to make a better money system, and other solutions I did not all publish yet. This does not involve any symmetry.
Something odd in your essay: you wrote "If the universe is closed, then its total energy will be zero." Where did you get that ? On the contrary, the measure of the thing related to energy that is conserved (that is not exactly the energy but something related to the difference between the energy density and the square of the expansion speed), is nonzero in a closed (spherical) universe. More details in my page on cosmology. Of course, the total electric charge in a closed universe is zero.