Did nobody read FatherHLL's post? He makes it clear what the primary doctrinal errors that the Council condemned. Apokatastasis was not the most important error, although it was still significant.
And Shanghaiski's post is excellent, and should settle the matter. We take what is good in Origen, and leave the bad. And we don't presume to supersede the Church's judgment, which was guided by the Holy Spirit.
As for the idea that those in Hell can be saved, there is evidence that those who die in the faith can be saved from Hades through the prayers of the Church. There is also some more tentative evidence that those who die outside the faith may be saved through private prayers. I have even been told that the Russian Church has specific prayers to be read over infants who die unbaptized, but I haven't found this in Hapgood's translation of the service book. If anyone knows more about this, I'd be interested to hear about it.
So there are grounds for hoping that those outside the Church may be saved, and certainly that those who die in the Church, but who have not borne fruits worthy of repentance, may also be saved by our prayers for the dead. But in regard to the former, the Church does not take it upon herself to offer up prayers, leaving judgment to God alone.