I did another migration last week. When I did a DB restore using the outlined method from an older setup I found the MySQL table slightly different on the old server to the new. This caused errors. Fortunately the symbiosis-mysql-restore script has a switch to restore individual databases. While I could have used other tools, this made it really simple.
To restore an individual db use the following > bash symbiosis-MySQL-restore -d your_db_name -u root
Doing it this way meant I did not need to change the debian-sys-maint password, just the user related to the database which was simple in phpmyadmin.