You keep saying that the position of St. John Cassian was condemned by an Ecumenical Council. This is simply not the case. And the fact that you think canon 111-113 of the canons of Carthage apply show the degree to which you do not understand the teaching of St. John or the Eastern idea of synergy.
Yes. St. John, and the Orthodox Fathers in general, accept that as man has free will, man has the ability to turn towards God without a specific act of Grace on God's part. What Orthodoxy does not teach (and what is condemned in those canons) is that man, having turned his will towards God, can accomplish anything at all without the extension of Grace by the Godhead--of course that Grace is always extended and so as soon as man desires God, God is there to fulfill that desire.
Or, to put it another way, Orthodoxy recognizes that the God has given the Grace of salvation to *all* men already. Therefore, the argument of Augustine and Pelagius was slightly beside the point (not that Pelagius wasn't a heretic, but St. Augustine got it wrong by allowing Pelagius to define the terms of the argument). God has made salvation available to all. His Grace (which is His Divine Energies) fills all the earth. All it waits on is for the motion of the human will to submit to it. All achievement that comes thereafter, is done by the Grace of God--as the canons say--but it remains the part of the human will to submit. One can put it that the submission itself is possible through Grace--but only if one recognizes that that Grace is available to *everyone*, both those who avail themselves of it, and those who do not. Or on can say that the submission occurs 'freely', in the sense that since Grace is available to all, one cannot say that 'he received Grace, and therefore was save' and 'he did not receive Grace, and therefore was damned'. Rather, they both received Grace, and 'he chose to submit, and he chose not to, and each reaped the consequences of their choic'.