Here's a demo of Hakkoryu Niho Nage that can be used for reference and comparison: https://www.facebook.com/photo.php?v...type=2&theater
So, in one's respective art, what would be used to generate similar ukemi against someone who is bearing weight forward and down to defeat the Hakko Dori / Aiki Age?
Sorry but I don't exactly understand the question!?
What do you mean by "to defeat" the Hakko Dori/Aiki Age? If you mean what principles are employed to execute the technique, then it is the same - bodyweight and kuzushi.
This is the kihon waza version whereas the Hakkoryu demo appeared to be more of a henka waza version.