Creating a script to edit file info

Do you mean an AA3 type script or a computer batch type of thing? Audition scripting of the variety operational within AA3 won't do file operations, hence they only work on audio files already opened in Audition. So no good for your purpose I'm afraid.

For editing meta data within audio files I use Metadata Touch. Not free but worth the outlay if you need to do a lot of metadata editing.

MetadataTouch - Powerful Multi-Format Metadata Editor