lolz...sorry, I couldn't resist!
Most people use
Calibre to perform their ebook library functions. It's a great tool to fix all the stuff you are talking about. By default, however, Calibre keeps all that metadata within its own program/database. If you want to fix the metadata in the ebook file itself then you'll need to take an extra step after you have corrected all the errors...you will need to either "polish ebook" or "save to disk". Either of those Calibre functions will save the info back into your file.
Cheers!