I’ve heard that about the Oriental Orthodox. A discussion I had with a particular Copt seemed to debunk the idea that they equate nature and person, but that was just an Egyptian kid on the internet not a professional theologian. I suspect like in any large group there are differences of interpretation within their community. For all I know there may even be situations like that of certain Catholics who seem to deliberately try to live up to anti-Catholic stereotypes, or, in my impression, certain ancient Nestorians who really held the heresy that was probably intended by neither Nestorius nor the modern Assyrian Church of the East.
Very interesting information about Eutyches. Never encountered the idea of restoring his reputation before, as has become common for Nestorius. Not to discount any individual instance like this one, but I feel like the way things are going pretty soon people will be saying Arius and Pelagius were just misunderstood too.

Again, you raise fascinating points!! Arius was included in the calendar of Saints under June 6 as “St Artotis” until the Bollandists, having discovered this deliberate inclusion by an ancient Arian copyist, expunged the name. But Arius can never be rehabilitated as he always held to the phrase “there was a time when He (Christ) was not.” Despite this, there are Arian saints in the Catholic calendar like St Nicetas the Goth, St Sabas the Goth and St Artemius the Dux Augustalis of Egypt. Martyrdom appears to have made the Church overlook the defect of their orthodoxy.
Even Wulfila, the Apostle to the Goths, who was at least a Semi-Arian, had a cathedral built in his honour at Trishtov in Bulgaria (ancient Novae in Moesia in Roman times), so even he was locally venerated.
Pelagius or Morgan of Wales has been given close scrutiny in recent times. There are independent Celtic churches in the U.S. named for “St Morgan of Wales” who was, in fact, Pelagius. The contemporary jury is still out on him.
The dispute between Alexandria and Antioch over Christology was based on these Churches’ different theological approaches - the former emphasizing the One Christ and the other the distinctions between His two Natures.
These disagreements spilled over into other Churches, especially the “Roman province” of the Church (the name the Alexandrians and Antiochians gave to Rome/Constantinople). St Flavian of Constantinople was beaten to death because he was perceived as defending the Nestorian position. Even the great St Nicholas clobbered Arius at the first Ec. Council because he felt the punishment exacted on Arius by the Council was not nearly enough . . .
I personally feel that Origen of Alexandria should, at the will of the Church, be canonized since his errors were such that he submitted himself for correction to the judgement of the Church. He was also honoured as a Confessor locally at Alexandria (had he died a martyr, he would probably be in the calendar now). That is my personal opinion which I too submit to the judgement of the Church.
Tertullian, although a schismatic, did much good for the Church with his polemical treatises and defense of Catholic doctrine and discipline. I don’t know how one would get around the fact that he did go into schism however . . . There was a Tertullianist church in Africa as late as the seventh century which did honour him as a saint . . . I’ll stop there . . .
Having said all this, there were numerous sects in the early Church with many wild ideas about theology. They had their own saints and martyrs and the veneration of such was forbidden. This did not apply to most saints of the Nestorian, Arian and other persuasions which later reconciled with the Church.
With respect to that kid on the internet, you are absolutely right, there are many who want to live up to a persona (whether it be Anti-Catholic or what have you) without knowing the current official state of ecumenical affairs. Like that convert who wore several rosaries and prayer-ropes . . .
Alex