The freedb (local) is for tagging information if you have downloaded data in the freedb format. Freedb usually supplies only data to the extent of V1 tags.
The export feature of MP3tag allows you to create more or less any kind of text data.
If you agree on a format for export and import then you can exchange the data.
The import feature in MP3tag works in 2 modes:
Mode 1: number and sequence of target files and records in the data source match.
Mode 2: a data field in a record contains the filename that matches the filename of the target file and in that way aligns the record with the target file.