A. The 'workaround' appears to be a valid solution, all we/they are trying to do is NOT backup the MySQL 'state' data, which is not relevant when restoring user databases and their tables. Explanation: the MySQL database construct will not be in the same state at some future date when you may want to restore the data (in fact you could whack the specific MySQL install permanently). The reason for the 'needed fix' is that the script was written before performance_schema became a default table.
B. Once I have made an adequate alternative backup of my 'real development data' on this LAMPP box, I'll contrive an experiment to test if the restore works. Unfortunately, the backup data is stored in a binary object whose structure is intended to be executed (as opposed to being read). SO it appears 'only the brave survive'.
C. Learning Webmin, rsync and/or the MySQL CLI (command line interface) resolves EVERY ONE of these concerns
Good Luck to all