Thanks for your questions, they show that galprop documention is not as good as it should be.
However the first question should be answered by Section 3.4 of the Explanatory Supplement.
26=Radial bins, 1=z-bins (z=0 only as described there), 63=energy bins, 92=nuclei described by the header keywords.
If it is not clear enough let us know.
The healpix files can only be plotted with routines which understand healpix like CDS Aladin http://aladin.u-strasbg.fr
and for that you also have to copy the vectors to a new column. I don't know what skyview is or what it can do.
On the other hand the format=2 (l,b) format is simple to plot, using ds9 or fv. But it is of course distorted away from the plane.
For the polarized synchrotron, this is not yet ready in the public version, so better ignore it for now.