"My" (Orthodox, not personal) Church does not canonize saints as they are canonized in the west (proof of miracles and what not). Orthodox Saints are those who are venerated because the faithful have recongized the goodness of Christ in them (their life, suffering for faith, extreme humility, etc. all Chirst-like characteristics). Orthodox saints are "sainted" when people spontaneously begin venerating them, not when the "Church" decides they are saints.
But we don 't presume than anyone is saved, for we don't know their whole book. Only God does. Saying that anyone is saved is claiming what only God knows by His own judgment.
Not even the Mother of God? Correct me if I'm wrong (I don't know if it's dogmatic or not) but I thought that the Orthodox held the Blessed Virgin to be perpetually sinless. If this is the case, then how can you not presume that she is saved?