Have you managed to get this to work, or what is the particular issue?
Seeing "%fontmeta" in there reminds me of the unbreaking which I did back then
for adf-accanthis-fonts.
The upshot was that a packager suggested new font packaging macros which required a change
in rpm (or base macros, don't remember), moved some font packages to the new macros
and then rage-quit when the rpm changes were not accepted, leaving some font packages in a
state of FTBFS. I unbroke the package above by undoing some changes, (maybe unnecessarily)
removing %fontmeta, undong some %expand-magic and adding back "-a" to a few
calls. I would hope that the current template leads to a working font spec for a simple
font, but the templates might be from that mentioned phase, and I haven't checked
whether the rpm side ever got changed. Maybe take this to font SIG?