2) The Ek comes from a private comm. as stated. The composition was as stated.
The idea of the DB is to have everything on the same scale, which in this case was not trivial.
In this case an additional entry for the original values would be appropriate, but then would need a flag to show the meaning of the values.
This paper
http://adsabs.harvard.edu/abs/2010arXiv1011.0989P uses AMS01 He, so it will be useful to see how they do it. In fact they discuss the difference between spectra on the Ek and momentum scales, and have to interpolate in order to get them.
In future we could ask experimenters to give spectra binned on both scales.
3) sometimes the authors give the mean, in that case I use whatever is given.
Sometimes only the range is given, then I compute the geometric mean.
The user can also make their own mean from the range.