This isn't a Django problem. Just don't customize the admin. Ever. If the admin can't do what you want, pull out React and Django REST Framework and build something that does what you want.
Point 3 ("WEB SITES ARE DEEMED UNSAFE, EVEN IF FACEBOOK MONITORS THEM") has been addressed. Here are the other two.
"YOU CANNOT BRING YOUR CONTENT IN TO FACEBOOK"
False. Facebook's API allows all sorts of external content to enter Facebook. They're just shutting down their app that does that automatically. There are plenty of third party apps that already solve this problem.
"PUBLISHERS WHOSE CONTENT IS CAPTIVE ARE PRIVILEGED"
False. The Washington Post has chosen to embed their stories within the Facebook canvas pages, but that's not a requirement. The other popular news sites on Facebook, The Guardian and Yahoo, do not do this.