I don't believe so from any of my reading.
From a non-OO source a brief summary of the situation says:
One of the last possibilities of reconciliation took place in 535 when Severus journeyed to Constantinople. His visit was very successful. He stayed there for 18 months and won over Anthimus of Constantinople to the Non-Chalcedonian.
Justininian was at this time attempting to win back Rome having recovered North Africa. Pope Agapetus made it clear that there could be no alliance with Rome if a critical position vis-a-vis Constantinople were adopted.
Justininian called a local council which banished Anthimus, charged Severus perversely with magic and banished him together with ordering the burning of all of his writings. Severus returned to his monastic retreats in the Egyptian desert.
Worse than the mere failure of these conferences, Justinian then re-inforced his opinion by legal means once more. From another historian and theologian:
"Emperor Justinian ratified the decision by issuing an edict on 6 August, declaring it criminal to maintain a non-Chalcedonian position in the empire, and he ordered the burning of the writings of Severus. Ephraim of Antioch also convened a council of one hundred and thirty-two bishops, which confirmed Chalceaon and condemned Severus and his followers.
The edict of Justinian could not solve the religious problem in the empire. What it did, on the other hand, was to declare the Chalcedonian body alone to constitute the religion of the state, in the same way as the Act of Uniformity of 1662 in British history did with Christianity in England. The edict was indeed injurious to the non-Chalcedonian body at least in three ways. Firstly, churches and other religious establishments in the empire became by law the possession of the Chalcedonian body; secondly bishops and leading clergy of Chalcedon’s ecclesiastical opponents had to spend their days either in exile or in hiding and new recruitments were forbidden. and thirdly, laymen were denied the possibility of obtaining positions of dignity in the state.
In spite of these handicaps, the people followed their non-Chalcedonian religious adherence in Egypt, Syria and elsewhere in the east. Since city churches and other institutions had been made available to the state church, they had to build churches and monasteries outside the cities. The church of Egypt, for instance, had to give up Alexandria and move its ecclesiastical centre to Enaton, where it built up monastic communities, six hundred of them. The Syrian patriarchs who claimed continuity to Severus had their residence in places like Haran, Callinicus, Edessa, and Mardin in North Syria. In fact, Michael the Syrian reports that the first time a non-Chalcedonian patriarch of Antioch ever set foot in that city, after Severus had left it in 518, was in 721, when patriarch Elias visited Antioch for the dedication of a church which he had built in the city. "
So after that time it was virtually impossible that there could be reconciliation. If you held to the Non-Chalcedonian position you were a criminal and treated as a criminal.
Early in the 7th century we find:
"John of Ephesus, who lived in Constantinople at that time and who was himself subjected to severe torture, has preserved for us a fairly detailed account of this persecution. At the beginning of the week before the Palm Sunday of the year 571. he writes, emperor Justin II issued an edict proscribing the non-Chalcedonian body. He ordered their places of worship to be closed, their bishops and priests to be arrested, and all their congregations to be disbanded."
Later on in the 7th century we find:
"Heraclius was again angry, and wrote to all areas of his dominions that ‘those who would not accept the council of Chalcedon should have their noses and ears cut out and their properties confiscated’. The persecution thus inaugurated lasted for a while, during which the severity of ill-treatment and oppression led many monks to endorse the council. But those who refused to surrender were forced by various methods to conform."
So again there was no likelihood of reconciliation.
After this the Arabs invaded and the Non-Chalcedonian communities were generally cut off from the Byzantines until they too fell under Ottoman control.
So I do not believe that there was even the possibility of reconciliation, nor of representation at the latter councils by virtue of either the political situation in respect of the Arab invasion, or the legal situation in which it was illegal to not accept Chalcedon on pain even of mutilation.
On the positive side the closest point came just after 566:
"Following this incident, unity talks were held between the leaders of the Chalcedonian and the non-Chalcedonian sides lasting for a period of over one year. This was a time when the non-Chalcedonian leadership was keen to accept an honourable settlement, without their having to endorse the council of Chalcedon in a juridical sense. The emperor granted this point, as the edict which he issued as a basis for union sufficiently shows. It noted the creed of Nicea as confirmed by the council of Constantinople as the only acceptable symbol of faith, and this creed as it had been interpreted by the council of 431 alone as the doctrinal standard of the Church. After incorporating the creed, the edict went on to affirm ‘two births of God the Word, one from God the Father in eternity and the other from Mary the Virgin in time. We confess him to be God the Only Word in truth, who remained unchanging in his Godhead. He suffered in the flesh and performed wonders as God, not as one and another; not that one is Christ and another is God, but one and the same, being composed of two natures of Godhead and manhood one hypostasis, one prosopon; not two hypostases or two prosopa, or two sons, but one hypostasis of God the Word incarnate’. The edict condemned all heretics, among whom were Nestorius and Theodore, as well as the letter of Ibas and the writings of Theodoret. ‘We accept the blessed patriarch Severus and revoke the condemnation that had been pronounced against him wickedly and without reason, and we lift the anathemas declared from the time of St. Cyril to the present time.’
The non-Chalcedonian leaders who saw the edict proposed two amendments. In the first place, they suggested that the statement on the incarnation should be modified from the words. ‘another is God, but’, to ‘read he who is one the same being composed of two natures, namely two hypostases, divine and human, and forming one nature, namely one hypostasis, divine and one prosopon. He is not two hypostases or two prosopa, or two natures or two sons’. Secondly, they asked for the inclusion of the twelve anathemas of Cyril as an accepted document of the faith.
Syrian historians testify that the emperor agreed to adopt the amendments and ordered that copies of the edict be made incorporating the changes, but that the men who undertook the work omitted them. The emperor was annoyed, but later cooled off. The non-Chalcedonian leaders, seeing that their proposals which the emperor had admitted had not been put in, refused to sign the document. Thus the edict could not serve the purpose for which it had been drawn up."
Thankfully things are different now.
Are any of these quotes helpful?