Interesting theory on the Vega-Tables seperate listing from The Elements, but you're wrong about one thing: They were
not "listed on the back", because the SMiLE album was
not finished. They were listed on a dummy for the back based on a cobbled together track list of uncertain origin.
I do agree that Holidays would work well as part of The Elements, to me as earth rather than air. But as the BWPS lyrics to it seem to be mostly from 1966, it is unlikely that Holidays was conceived as part of The Elements. Of course, it found its place in the elemental suite on BWPS!