Owen,
Good questions, with easy answers, at least from the perspective of the discrete self-similar cosmological paradigm [aka Direte Scale Relativity when the cosmological self-similarity is exact].
1. If you study nature's hierarchy empircally, and very carefuly, you will find one and only one pattern of Scales and "internal" levels that maintains a high degree of self-similarity. This is a key universal symmetry that has not been fully apreciated.
Within each cosmological Scale there is a subhierarchy of levels [e.g., H, He, Li,... DNA, ...comets, ...]. This may correspond to what you are thinking about and calling "internal ranks". The cosmological Scales are related by exact discrete self-similarity. The self-similarity within any given Scale is much more continuous and can range from near-exact to merely statistial.
2. Discrete Scale Relativity firmly rejects a 0th Scale, since only for an infinite hierarchy can there be exact self-similarity.
Even sticking to the slghtly more conservative DSSCP with less exact self-similarity, the idea of a "bottom" to nature's hierarchy makes a good natural philosopher want to vomit.
DSR takes some work because the ideas are very new and radically conflict with some old ideas. But once one gets the basics [i.e., the basic scaling equations, division of nature into Scales, appropriate analogues of fundamental systems on the different Scales] one's progress comes much faster.
The website is full of empirical examples from nature that argue for the uniqueness and correctness of the paradigm. There are also theoretical results like deriving the mass and radius of the proton using the Kerr-Newman solution of the Einstein-Maxwell equations, as trivially augmented by DSR.
I am ready and willing to help anyone with a genuinely open mind to understand this new paradigm. I confidently predict that it will be the paradigm for physical and biological science for the 21st century. [I am not lacking in chutzpah, obviously ;)]
Yours in science,
RLO
www.amherst.edu/~rloldershaw