Looking for guidance on Files Object. 

Is there a way to create a custom list view of all content records. Nothing obvious in set up or in help documents

I am unable to modify the page layout for Files, and cannot add a custom field. I would like to associate files with our unique code for Opportunities so we can flag them and associate to the parent Opportunity both for SF internal files, and thousands we have on an external platform. Any idea on how to do this?

Is there a way to mark all files as shared with all internal users by default?

As usual, any pointers most welcome