( 
at non-RC purgatorial post-mortem punishment being a “Romish” superstition. Of course, that must be where all those Syrian and Alexandrian and non-Latin remedial punishment Fathers going back at least as far as the 2nd century were getting it: from Romish superstition. 
)
If the situation is ending, then it’s referring to a temporal situation. Nor does the situation have a timeless non-beginning in the past.
Flexibility for eonian doesn’t decisively settle anything; it’s just an example illustrating that context matters. Even if three quarters or four-fifths of the adjective’s use in the NT applied demonstrably to temporary things or situations, the adjective could be still be used consistently to describe some kind of endlessly hopeless punishment in its remaining uses. In theory, it could have been used exactly one time in the NT to talk about an endless thing or situation, which could have been punishment for someone, and every other usage could have (theoretically) only referred to temporary situations or things – and that one ‘eternal’ usage could have still been perfectly valid and accurate. (I’m pointing that out to be fair.)
The term demonstrably doesn’t hold such an ironclad usage in favor of never-ending continuance in the LXX (which is just as ‘inspired’ as English translations, if not moreso); and it demonstrably doesn’t hold such an ironclad usage in Greco-Roman culture (whether Greek or its Latin derivation term avum) up through the time of Jesus; and it demonstrably doesn’t hold such an ironclad usage in at least once in the NT canon (at the end of Romans), since the usage could have theoretically hardened in Palestinian or Hellenistic Jewish culture; and it demonstrably doesn’t hold such an ironclad usage in the Patristic authors for several centuries afterward.
That leaves the door open to the linguistic possibility that Jewish-culture authors, writing in Greek in the mid-to-late 1st century, didn’t always intend it to refer to never-ending continuance elsewhere in the NT. So immediate, local, and extended context has to be the deciding factor on a case-by-case basis. It might have that temporary usage for every other NT instance except in part of one verse of Romans; or other uses might involve temporary situations or things, too.
Either “the death” (it has a direct article in Greek) refers to a state or event of death, in which case universalism must be true since ongoing death in ECT or final total death in Annihilationism wouldn’t be the same as death itself being destroyed; or it’s a Jewish euphamism for Satan. If it refers to Satan, then either Satan is an impersonal power or a personal creature. If Satan is impersonal, then Satan’s annihilation out of existence doesn’t even slightly count against universal salvation of all sinners from sin. If Satan is personal, then Satan’s destruction involves him being subdued to Christ eventually in the same way that Christ is subject to the Father, so that in their shared subjection under the leadership of Christ God will be all in all. And if the worst possible rebel is destroyed that way, then we have no reason to expect lesser rebels to be destroyed in some other way that doesn’t involve them also being put down and subjected personally to Christ and in cooperation with Christ to God the Father.
There really isn’t any coherent way to get something other than universal salvation out of that; and trying to read non-universalism into it (which could be theoretically proper with a proper rationale) ends up voiding parts of the teaching in completely antithetical ways.
Biblical tradition has sheol/hades in several kinds of places, with rebel spirits trapped in the air immaterially, trapped in large bodies of water, trapped in the cold dank ground, trapped in the roots of the earth (a combination of cold water and cold earth). There’s some volcanic imagery, too, every once in a while, although so far as any spatial imagery is used that seems to be on the surface of the earth.
Western tradition afterward (thus Christian in shape, let’s say) tended to think in terms of the center of the Earth being the coldest, deadest place in Nature. Not the hottest. Even in the shift from geocentrism to heliocentrism was ideologically a change from the center of the universe being the (almost literally) crappiest, deadest, coldest place (on the principle that crap runs downhill – I’m not even joking, that was the basic principle, heavy and corrupted things settling downward), to the center of the universe being the most important, brightest, hottest, and (in ethical typology) the ‘best’ place in Nature: obviously the Sun.
The idea of hell being a hot place in the center of the Earth, is relatively recent in Western culture. (Not sure about Chinese culture or Mayan or other cultures, but since they aren’t Judeo-Christian in character their history is irrelevant for this purpose.) It started developing sometime after Dante’s Inferno – where “inferno” meant something practically opposite to what we think of by the word. It was basically a Latin-derived term for hole, and Satan is frozen there in ice at the center of the earth.
Re God as a consuming fire: depends on what He’s consuming. A refining fire consumes impurities in the alloy, and everything that can be shaken will be shaken until only the unshakeable remains as the Hebraist says nearby. That isn’t refinement imagery (as far as I know), but it’s remedial, and this all comes at the end of a chapter that’s largely about explicitly remedial punishment. So actually, yes, the consuming fire description is connected by immediate and local context to remedial, not hopeless, punishment, of misbehaving children whom God intends to inherit.
That said, there are OT citations in the background (primarily Isaiah 33 if I recall correctly) which look more harsh in their nearby context.
