As I pointed out in the OP, the "higher plane" doesn't even actually require the 8th sense to get to in the first place and is completely unrelated to it, which is a key detail left out in the last thread. Asmita and Sisyphos get to it before awakening it (the whole point of them raising their consciousness to contact Illias there is to learn more about it).
This confuses me a bit. 8th sense users being able to go there voluntarily doesn't preclude other forms of life getting there. Randolph Carter sure isn't 1-A as a human but goes to many higher dimensional realms outside of physical reality in his escapades as an example.
You also mention them being there as anti-evidence but then stated "the whole point of them raising their consciousness to contact Illias there was to learn more about it". So it sounds like they weren't actually able to get there? I would need more context but this seems more or less like someone getting into heaven after death naturally vs a human or disembodied spirit which can freely move between heaven (in this case higher dimensional) and other planes. In this case both people actually needing enlightenment in order to get to such stage of knowledge.
Also the gaining knowledge of the world part is fine, but it's not evidence for qualitative superiority or a higher spatial dimension (HDE).
It can be within context. For instance, in Persona, there is an Akashic record that houses all events and memories of existence. This fundamental nature allows one to see across all of time and space, gain knowledge one wouldn't have, etc. so alone it's not proof but it is sure as heck good supporting evidence.
Well, it's not just the facet of their thoughts ascending, I also detail in the OP how the higher plane actually doesn't have to do with the soul or their souls actually going there, as it's a place created by and characterized as their own thoughts that they perceive by looking deeper within themselves and simply raising their consciousness.
The scans make it pretty clear that it is indeed their cognition that is ascending. I think a very important context being left out is the blatant inspiration from Buddhism here. Ascending to deeper parts of reality via raising one's consciousness would indeed lend itself to this idea especially if the core of reality is mental in nature, which is what it seeming to be proposed from the scans I left.
Their literal souls nor bodies don't actually go there, Ilias' soul is even confirmed to be existing integrated into the normal world.
Can you please link those scans? I'm not sure why cognitions would not be a part of the soul, nor does the whole asmita stuff really make sense.
I also have a problem with your refutation regarding (in my opinion) one of the more important scans.
This is so grossly out of context it's hard to think where to even begin.
Asmita here is saying that the higher plane Illias was in felt as if it were beyond some thin impenetrable membrane, but now he'd finally reached it. The statement by nature is a metaphorical comparison and not literal, and even if it were literal, he never calls it some higher dimensional membrane or anything like that in the scans, nor does he make any note of the universe. And also, from the above, we already know Illias spiritual existence was in the regular world, and this in reference to his mind/consciousness.
The actual context of this realm that Illias's mind reached and his state of being and how they get there makes it clear this interpretation makes absolutely no sense of it being some 5-D higher spatial dimension or dimensional transcendence to reach it.
This is false and belies my earlier point of lacking context in the buddhist themes.
Here in
the scan, as this "metaphor" is being discussed, you can clearly see Shaka holding up the Diamond Realm Mandala of Vairocana.
This is important because it is touching on the themes being discussed. In buddhism, the womb realm is the realm of physicality and manifestation. It is where ever changing things happen and nothing is ever permanent. The other realm is the diamond realm, and it is one of pure transcendence where all the static archetypes that exist a priori to and craft the lower realities. The diety Vairocana sits there and the eternal archetypes are simply thoughts that arise from his meditation in the void. Vairocana also being synonymous with the universe (in totality, not the physical 3-D verse) itself.
With that context in mind I think it's pretty clear that the "higher dimensional stuff" the stuff about "thoughts being transmitted to this realm" and the whole you can't go to this realm without the proper cognition" all point to this interpretation, which would indeed grant HDE.