Logo for FBIA is added through styling settings in FB, not in the plugin.
I have them working, in FB audience network nothing is selected, only the ad number is added in the WP plugin settings
Yess,
What I want to say is these related articles which you see in FBIAs are auto generated, based on enagegement from FB, not from your blog.
When you have a lot of views and likes for some post in FB, then it will be added in the list.
They wıll be shown automatically, when some article have lot of likes and views.