If we consider the main sources of Dzogchen...:
Tonpa Shenrab Miwoche, the Twelve Dzogchen Teachers (Nangwa Dampa, Dorje Chang, Ngöndzog Gyalpo, Budddha Shakyamuni, etc.), Garab Dorje, Tapihritsa, Drenpa Namkha, Guru Rinpoche Padmasambhava, etc.
...there's no need to say that Dzogchen developed from this particular place, or a from that particular combination of other traditions, etc.
Dzogchen came from Dzogchen, even if its historical development was influenced over time by other traditions (whether it be Indian Vajrayana, Anuyoga from Sri Lanka and Kyrgyzstan, Chan/Zen, Shaivism, Taoism, Zoroastrianism, etc.).
I'm also willing to bet that the founders of all traditions (i.e. even non-Buddhist ones) were likely emanations of Buddhas (and Fully Realized Buddhas are Dzogchenpa's) anyway, if we consider how the Dra Thalgyur Tantra classifies all the Yanas.
I think that ChNNR was making the point that there were multiple sources for Dzogchen.
Having taken Nyingma, Kargupa, Bonpo and ChNNR's pointing out indication, I feel that they are all the same. Some emphasize this flavor or that flavor, but it is basically the same taste.
Certainly the specifics of the practice path are different, but perhaps the end is the same. I have never practiced, or experienced a pointing out from Chuan Chen Tao, and so cannot compare it. I've enjoyed reading about the Tao, and find a home there too, especially Chuang Tzu.
I actually am not interested in the origins of Dzogchen, or which school came first. This is not important to me at all. What is useful is what matters to me, and that does apply to Chuan Chen Tao, and any path of practice. From the point of view of awareness, how can I label myself as a this or that? Labels don't apply. As a Dzogchen practitioner, I prefer not to limit myself, while observing the minutia of karmic causes and effects. Ya do good = ya get good. The devil IS the details. That works for me.
What is important is how the experience of Dzogchen (or any path) can be integrated into my daily life. For this, the Teachings of ChNNR have been most useful to me.
What applies to me at this point in my life, did not apply at another. Certainly what works for me should never be taken as a "should," for anybody else.