I enjoy reading descriptions about how various people solve their problems. This is nice! One question I had was why the author uses softcover instead of pandoc. Is it a preference or a technical reason?
That being said, I've recently used pandoc for another project (a paper) and I really liked the result and the functionality (references using BibTex). Also, I see modern pandoc has support for MathML and even image math https://pandoc.org/epub.html#math so will be doing some testing to see how it works...