How to represent media as individual entities?
There is a module called Media entity. Some more details about it, from its project page:

Media entity provides a 'base' entity for media. This is a very basic entity which can reference to all kinds of media-objects (local files, YouTube videos, Tweets, Instagram photos, ...). Media entity provides a relation between Drupal and the media resource. You can reference to/use this entity within any other Drupal entity.
This module attempts to provide the base storage component for the Drupal 8 media ecosystem.

I think that it will do what you want.