@retroroscoe I don't have answers to your questions as a lot of people can make it work, I can only share what I've experienced.
Mysql stopped working for us at 5.7 on our 10.12/Sierra Server.
we weren't the only ones (Like i said, you can make it work) -- https://devmarketer.io/learn/do-not-install-mysql-macos-sierra-how-to-fix/ -- https://serverfault.com/questions/843878/mac-os-sierra-cannot-start-mysql
We moved our MySQL DB to a RHEL box and left tomcat / repository on the MacServer.
HUGE HUGE HUGE Improvement in performance. I suggest getting away from MySQL on the Mac.