The plans are as follows now:
We drop the old implementation of a single photo as being a slideonly show with one photo only, having the optional border as settable in Table III-A2 and having the linksystem as in Table VI-8.
We adapt the new implementation as you tested, but with line 0 in Table VI, equivalent to line 1 (for mphoto), i.e. its own link structure.
For single photos (Sphoto as opposed to Mphoto) there is no longer a border as implemented for the slideshow, see Table III-A2 and Table I-B4.
If you really want a (background) border, there is a new class
.wppa-sphoto to make it manually.
This is the quickest and most robust way with the less overhead as possible, still having the full wppa+ linkfeatures.
If you can agree with this (the only thing that disappears is the background/border and of course much overhead!) it can be released in a few days (needs changing some texts in the settings page, because some things apply no longer to fullsize and slideshow, but to slideshow only)