Do drafts means the same as unpublished post

Yes, both are the same thing.The terms are used to tell about the posts that are not published and are in the saved draft section.
Whenever you make any post on facebook but don't want to post it or forget to post it properly with any reason then it will be saved in the drafts section. And you can easily edit them when you want to publish.

Read More:- ityug247.com/how-to-find-drafts-on-facebook/