Perhaps this is something that's viable for me? I think all of my requirements could be met with a small(ish) Perl script? I would certainly need to use something like the CommonMark module to do the markdown conversion, but a lot of the rest I could handle myself?

pros

• less complexity, it would be much more pared-down than Jekyll
• I would understand the code much better, so some changes could be made much faster

cons

• if we end up needing several more features, then we would end up needing to write all that ourselves, whereas with Jekyll, there's a huge amount of functionality and modules already written (don't reinvent the wheel... though some people think reinventing is appropriate sometimes [2])
• "roll your own" is often associated with poor-quality code, a not-invented-here mindset, and someone who gets in over their head because they end up needing to write more code than they originally anticipated, code that may be outside their experience level

short summary?

If anything, "Don't Reinvent The Wheel" should be used as a call to arms for deeply educating yourself about all the existing solutions – not as a bludgeoning tool to undermine those who legitimately want to build something better or improve on what's already out there. In my experience, sadly, it's much more the latter than the former.

(emphasis mine)

There are also these guidelines to help make the choice.