After about three days of banging my head over missed commas, extra commas, missed backslashes before single quotes, and so on, I have finally been able to "compile" the entire AboutTh.is database design spec, (i.e., no MySQL errors)! It used to be a matter of professional pride that I would try to write code so that it was compilable on the very first pass, but that was twenty-to-thirty years ago, and I'm just a wee bit rusty. Also, I'm not very experienced with MySQL yet.
Things I learned about MySQL over this process:
Comments use an equals sign for tables, but no equals for rows. Why be consistent?
Foreign key constraint identifiers need to be unique across the entire database, not just within each table.