finally had some time to revisit this
Did a test conversion of order entry and this time with the new CK in 19.1 the conversion went through without a hitch
we used the newest MariaDB ODBC driver.
this was order entry only. Have not tried a more complex system or connecting to an existing MariaDB database yet
Now we just need to get rid of the annoying INT files so we can start using Liquibase for our automated data migrations