Hm, I think this probably springs from us having different ideas of what NEP entails all-in-all.
I think it really only runs into a logical problem if you insist on saying that characters with NEP really are nonexistent, which I thought was something we generally rejected. Characters who personify voids of nothingness or something are strictly speaking just weird states of existence and not actual philosophical "nothing," as the page itself notes. I don't think there's a problem in saying Tier 0s are 'beyond existence and nonexistence' in the sense they transcend conventional existence (And extensions thereof) and also all such weird states.
Well, as the page specifies, the idea is basically that they are nonexistent in some aspects, but not in all. And they can be that either literally, in some transdual or in some paradoxical sense, but nonexistent they should be. Hence why not every character with nonduality regarding existence/nonexistence would have this, but only those whose nonduality behaves nonexistent in some sense (e.g. characters who are erased even from the state of not existing).
The type you specify appears to not be nonexistent in any aspect (or not differently nonexistent in the aspect than other types).
Basically, I don't think nonexistent physiology would cover "above the distinction between any states of existence and nonexistence, on all possible levels", since that's not nonexistence on any level or in any sense.
You might want to consider making something like a "Monad Abilities" page, where you simply gather all kinds of Tier 0 exclusive abilities. Since they are reserved just for them, there probably is no actual need to even try to integrate them into regular separate pages.
Strictly speaking, the law of exluded middle is broken when you start messing up with contradictories, e.g. "This guy is neither red, nor not-red." But it's not really a problem when these oppositions are not contradictories but just contraries instead, like, say, a shirt that's neither black nor white.
A shirt can be neither black nor white, because those are not opposites and it can be in a third state, like red, instead. Doesn't seem like a good example.
But we talked about that quality theory of yours already. I get the principle. A Monad is not supposed to be "Neither red nor not red", but there is supposed to be a quality (i.e. concept) of, say, "being red" and the Monad just lacks the quality of redness, but there is no "quality of not redness" meaning that the monad lacking all qualities does not imply it is not red, avoiding the contradiction.
The problem is that your paragraph doesn't really properly explain that view.
Any unintroduced reader that is presented with the statement "completely transcend all individuality, all differentiation and all particularization, and therefore are above the distinction between any states of existence and nonexistence, on all possible levels" will assume that this means that the character, in terms of properties not qualities, is "neither existent nor nonexistent" with nonexistence being defined as the logical negation of existence.
To not be understood in a way that conflicts with the law of excluded middle, I think you will probably need to actually mention the idea of qualities and how it differs from logical properties and their negation. So that probably is the way to go here.
In case you missed it, Ultima formulated a way to phrase that; how do you feel about it?
Hmmm... I don't think the problem is that a Tier 0 needs to make multiple things happen at once?
Isn't it rather that Tier 0 entity in essence can't change their mind, shouldn't act in reaction to events and essentially must have already made everything that it will ever make happen happen, as there is no such thing as time or subjective order of events for it?
By the way: While I've agreed that "Large Size" as an ability is better not extended to 1-A-through-0, I suggest that we cap it out at the Type 10 I suggested:
Type 11 is completely redundant once we exclude 1-A from the ability, since the highest types are then really just extensions of higher-dimensional space and the like. At that point we might as well try and make infinite subdivisions, which is obviously not ideal.
That sounds ok.