How to use author's avatar as Facebook post preview image when a single post is shared

Question

I want to use the post author's avatar if available as the post preview image for Facebook shared posts. If that is not available next would be a featured image and then a default image as a fallback. Is there a plugin or function that can achieve this?

The Yoast SEO plugin and many others can insert a default image, but I have not been able to find one that can pull the image from the author's avatar.

*note, I am also using Simple Local Avatars for users that do not have avatars associated with their email