robroy47 - these are my thoughts.
First take a backup of what you have.
I would find a way to isolate authors with 2 part names - e.g. 'Dickens, Charles' and move them to a separate library. Probably need to use a regular expression search - see
The search interface. I would then use the Bulk Metadata Edit, Search and Replace feature to reform the 2 part author names to FirstName LastName - e.g. Charles Dickens.
I would handle the remaining Authors, i.e. those with three or more part names individually - in the Manage Authors list. Probably have to handle books with multiple authors individually, and those with initials e.g. J. K. Rowling.
Then I would move the 2 part authors back to the original library
BR