I'm not sure if you're agreeing with what I said or disagreeing with it 🙁 I'll try and clarify some things anyhow :D. This will again get into a a matter of semantics but a lot of what you are talking about just depends on what your reference frame is. I use the recognized anatomical conventions for joint movement which are sometimes not used by coaches. Hyperextension can be a position or an action. In either case, it is still a sub-category of extension. If we are referring to it as a position, then yes, it is indeed a point where the foot is considerably behind the plane of the hips.
Also note that "hip extension values" as I referred to them in that post can range from total hip flexion (their is still an extension value or angle) to extreme hyperextension. What I was saying is that a lower than maximal hip extension value (far below the point of maximal hyperextension) is advantageous.
Also, basing technical speculation on one performer (ala Flo-Jo vs. Marion) is interesting but of little value because their are so many compounding factors. It is safer to look at a large sample of former and current champions as Stu suggested and as Ralph Mann has done.