Thanks for your replies.
If you can pray somebody out of it then by definition it isn't
gehenna.
Again, believing one can do so is as appealing but illogical as outright universalism.
As to who believes in what, searching east, you answered your own question regarding Rome by quoting their catechism.
As for Orthodoxy, AFAIK none of this is defined doctrine, because in the East nobody developed a following by denying prayer for the dead, just like there's no defined doctrine there defending true belief about the Eucharist.
Prayer for the dead is in that church's services as is opinion about the toll-houses (a form of the particular judgement
not the intermediate state) and Orthodoxy leaves it at that.
That said...
It seems from writings like Fr Seraphim's that the Orthodox have pockets of believers who deny an eternal hell for some people. Not formally heretical according to Orthodoxy - see above - but worrisome!
I've only seen
The Orthodox Word in passing for the past 20 years but
Not of This World/Father Seraphim Rose: His Life and Works [amazon.com] (the extensive revision of
NOTW is, as I wrote, a condensed compilation of it and everything else Fr Seraphim wrote.
Death to the World was/is a more recent version of the same idea.
The apocalypticism, like in certain kinds of Protestantism (
Left Behind), can be taken too far, but like with Roman Catholic traditionalism I like very much the orthodoxy, fervency, devout observance and sense of urgency about some of these things that Fr Seraphim and his
cultus (in the true sense - not 'cult') had/have.
)