They are, but he continues the narration beyond that. Consider that he both assisted the WoL in the battle against Elidibus, through his own presence (worded more clearly in the JP version of the poem in Ere our Curtain Falls to note that it is him and not just something contained in the crystal), and was also said to be hanging around in the Aetherial Sea in the White Day event, even if that is taken as mostly fluff. Ishikawa also never really confirmed his (or Lahabrea's) deaths. Elidibus, similarly, is trapped in the tower rather than dead. In all three instances, the major issue is that auracites have never meant their death, but rather expulsion into the Aetherial Sea. The EN version, doing its own thing as usual, parses this as "consigned to oblivion", whereas you get things like this from the French version:
There is also the fact that Emet-Selch (due to his sheer power) could not even be contained in the auracite, and that Lahabrea wasn't killed in the conventional way. According to Ishikawa he's in a similar boat to Hades:[20:48] Urianger : Une fois privée de son corps, une âme ascienne pourrait être enfermée dans une prison d'éther... Une lame éthérée serait alors en mesure de la briser, et l'Ascien retournerait ainsi vers la mer des étoiles.
= “Once deprived of their body, an ascian soul could be locked in an aether prison... An ethereal blade would then be able to break it, and the Ascian would thus return to the sea of stars.”
You will note that her answer is non-committal to the point of saying 1) his state is the same as Hades's and 2) it is believed that Hades was destroyed. I think it's also obvious that if everything up to the point Lahabrea endured in the eye failed to kill him, Estinien piercing it is hardly going to suffice.Toward the end of Shadowbringers, players defeat Hades without imprisoning him in the White Auracite. But Lahabrea was defeated in a similar way, and eventually returned. Is Hades is done for good?
NI: With Lahabrea, he wasn’t literally put into the White Auracite. But he was absorbed into the dragon’s eye, and Estinien pierced it. Although he wasn’t imprisoned in the White Auracite, you can technically say he’s in the same situation.
When Hades revealed his true form, and his soul was there, we didn’t capture it in the White Auracite. He was held down and pierced with a stake, basically. He was captured and not able to move at that point, and then the Warrior of Light struck him with the blow, so it is believed that Hades has been completely destroyed.
We've never known him in the flesh, anyway. He was possessing hosts all along. I imagine if he does return it'll either be through being pulled out of the Aetherial Sea/Underworld (he has power over it after all), or in a more abstract sense like Shougun mentioned.
Besides, it wasn't just Gosetsu who got heat for that, but also Yotsuyu and Zenos, mostly because their arcs were considered concluded. Gaius also drew heat for it. Y'shtola mainly gets heat for it because of the sheer number of times it's been baited now, and she comes out just fine.
Now, am I fond of it? No, not really. I think they need to re-consider when they kill off characters, if the approach is actually to wait and see how popular they are, and/or whether they're the best fit for a plot arc, rather than giving the impression of death, then going "well, ackshually!" and pointing to technicalities they implanted, because it certainly does cheapen the meaning of death.
IMO, Elidibus was offed prematurely and had much of his thunder stolen by Hades. Fandaniel has a very weak connection to the ancient world, and Zenos has none. Yet they still wish to push the storyline of the ancients and ancient world forward, which makes sense since it's integral to Hydaelyn and Zodiark, and interests a lot of players more than some brat getting his jollies off to his next big fight. So their options are either to carry this on with one of the sundered Overlords besides Fandaniel, use Venat, whose role remains very ambiguous/is not keen on memory of the ancient world, or bring back the ones they have already built rapport with... with Emet-Selch having skyrocketed to 6th most popular character in the FF series in JP, it would not surprise me in the slightest if it were him. They've also telegraphed this from all directions.
With that said, am I going to complain if they bring back Emet or Elidibus (or Lahabrea, which seems most likely of all)? No, particularly if I am already enduring a "back from the dead" character I find as pleasant as nails scraping a chalk board (hint: it's not Y'shtola.) I will sit back and enjoy the ride and just hope the writing is good.At least with Emet he is the one character where cheating death makes the most sense, being lord of the Underworld...