Evaluating Dark Energy Measurement Schemes

Several months ago I came across a video of a talk given by Carroll. I can't remember where it was but I was impressed by his compelling breakdown of the dependency of the "concordance" LCDM model on many poorly understood assumptions.
The talk centered around a theory flow chart that attempted to question every possible part of all the hypotheses on which the model is based. It was a very well written talk, in that he worked his way through the flow chart, adding to it as each question and possibility was addressed.
Now, in the white paper "Insights into Dark Energy: Interplay Between Theory and Observation" this diagram shows up again. I see this on the first page and I think, great a review paper that will go through that talk again except this time with details and references. My mouth waters.
Alas, tis but a shade of my desire. So many things in that flow chart are left completely unexplained. A short compendium:

1) Dust Reddening and\or Photon- axion mixing simulates acceleration

Axions are predicted to change to and from photons in the presence of strong magnetic fields, and this property is used for creating experiments to detect axions... Depending on their mass, axions could plausibly explain the dark matter problem of physical cosmology. --wp

I'd never heard this universe not actually accelerating thing before.

2) Strong Energy Condition violated required for a dark energy.

The strong energy condition stipulates that for every future-pointing timelike vector field , the trace of the tidal tensor measured by the corresponding observers is always non-negative:

--wp

Also, from Carroll's S&G we see that the SEC implies that "gravitation is attractive".

I don't know this is appropriate but I don't WANT the SEC violated. Feel the same way about violations of the Equivalence Principle. EP is one of the most beautiful thought experiment proofs ever! Who would be so cruel as to violate that?