1)"Critical Diversity vs. Critical Information": Fair question. Within the context of my essay it goes without saying that Diversity would not exist without Information; so in a sense Diversity is comprised of Information (which would make my claim seem circular/redundant at first glance). However, when a diversity of physical substances comes together there is also an Information exchange between them. This is what I mean by a critical density of Information accumulation during the self-organizing process. I postulate that through vibratory Information-exchange (similar to carbon and beryllium entering into resonant communication during the formation of stars) substances 'learn' to 'cooperate' with each other. Without Information (acting as a sort of 'medium of exchange') the substances would remain inert and inactive. This is a form of Information exchange that happens purely on the explicit level, whereas the emergence of Diversity within a singular object/substance in the first place is a different type of Information-exchange that takes place between the singular explicit substance and the implicit Information Field exclusively.
2)"The problem is that we cannot know because we are not able to reach absolute-zero Kelvin. We are close to but we cannot get it."
I could be wrong, but I'm not entirely convinced of that:
"All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy...This results in motion even at absolute zero. For example, liquid helium does not freeze under atmospheric pressure at any temperature because of its zero-point energy..."
Source: http://en.wikipedia.org/wiki/Zero-point_energy
"...nothing can be colder than absolute zero on the Kelvin scale. [However] Physicists at the Ludwig-Maximilians University Munich and the Max Planck Institute of Quantum Optics in Garching have now created an atomic gas in the laboratory that nonetheless has negative Kelvin values. These negative absolute temperatures have several apparently absurd consequences..."
Source: http://www.mpg.de/6776082/negative_absolute_temperature
3)"What are the waves made of and what is the vacuum?"
While of course my description encompasses all known EM-Waves (and theoretical Gravity-Waves), as to what they are at root level is difficult to speculate on. What I can say is that their geometric properties are a byproduct of some sort of 'mind-like' Information Field that allows them to develop their form/geometry (and therefore acquire meaning) in the first place.
I agree with your intuition that the 'quantum foam' is an epiphenomenon of sort originating from a deeper underlying vacuum-structure. Whether the vacuum structure is defined purely by charge-density, a neutral manifold/lattice structure (however you want to qualify that), or some combination of both is hard to say, but if I had to guess it is likely some mixture of the two. I can however certainly appreciate your characterization of this sub-structure as a purely 'neutral' elastic manifold that gives rise to the fundamentals of Nature (i.e. similar to what Mendel Sachs would have likely derived from his Quaternion GR Theory).
I suppose at its heart I conceive of the sub-structure more as an underlying fractal/holographic 'Potential Field' (formalized mathematically as the Quantum Potential and demonstrated experimentally by the Ahranov-Bohm Effect). You can sort of envision this substructure as an ordered, Brusselator-like gradient system (reaction-diffusion, oscillating, kinetic) that is the seat/embodiment of primordial Information that then distributes it throughout the known Universe instantaneously (which then gives rise to coherence via self-organization).
4)"For me it means that the geometry (form) is the key. Information and substance are the same thing"
While they certainly require one another, let me again quote from my introduction, "As a general rule Substance does the work of Information". So in other words I give the slight edge to Information, as did Bohm when he said, "I'm saying it's both; but information contributes fundamentally to the qualities of substance."
Thank you so much for your pointed questions/remarks and I hope these qualify as satisfactory replies. All the best.