1. How does Michael being absorbed into Rimuru, and thus feeling as though he is being returned to the world/Veldanava, relate to the "All Encompassing Oneness" still being a thing?
Because Rimuru clarified (in Volume 16) that despite many beings possessing divinities in slime, there is
none other like that "All-encompasing God". That itself makes these statements unique to one entity, the Godhead.
And, further, do you have any other scans to support the argument that there still is some overarching Oneness without division?
For example, the statement from Zegion about the truth of the world. The fact that Ramiris (as a proxy of God) can still grant it's blessing to people (for blessing to br given, the higher entity or whatever needs to exist first in tensura). Also thr fact that the Omnipotent is supposed to be not bound to cause and effect unlike Veldanava (according to Feldway)
At the current moment, I don't really believe that Veldanava has this "true state." To me, the scans read more that he literally did just dissolve himself into a more interesting exitence. And his avatar state is all that remains at the moment.
Veldanava doesn't, as explained above, Veldanava itself is simply an avatar, with God being a completely different entity.
I'm not quite sure what you mean by that last line, however, so I'd ask for you to elaborate.
2. They wanted to bring back the "Omniscient, Omnipotence" version of Veld. How exactly is it they planned to do that?
Apparently, Michael thought that uniting all skills (which were originally Velda's) into one would bring back the omniscient creator. But that theory was proven completely wrong by Feldway.
I ask because this is a pretty obtuse thing to say especially combined with the previous questions I have. It again supports the notion that Veldanava is completely dissolved from his previous Oneness that used to be.
My answer to this is basically my answer to your first question.
I again don't think the Rimuru absorption scan provides sufficient evidence.
3. You are trying to argue for High 1-A? Do you mean High 1-A+?
I made it clear that I'm fine with High 1A or any tier higher than that, but a minimum of High 1A.
Although, from my understanding, Ultima did give an example of one-being (high 1A+ thingy from what I understood, though I may be wrong) in the previous tier 0 thread trying to explain what veldanava could be other then a tier 0.
I do not understand how it could be High 1-A when there is not an established 1-A hierarchy in the first place which this transcends
It doesn't need a whole hierarchy to be that tier, said tier can be achieved simply by lacking the distinction between qualitatively different things, such as the distinction between reality and fiction (there are many such
obvious differences in tensura, such a s between Diablo's imaginary world and the real world.)
I got this method of getting High 1A from one of Ultima's sandboxes/blogs, just to note.