It would be really nice to have a built in Diff tool to compare database structure / tables & fields with known baseline to identify detritus so we can manually drop columns and or entire tables.

what you can do right now is install a fresh IPS and compare the table structure

https://dev.mysql.com/doc/workbench/en/wb-database-synchronization.html is a guide to do this with MySQL workbench. There are other MySQL schema comparison tools out there as well.