Likewise, it's not exactly uncommon for time travel (Or any action / process that affects something through different points in time) to be described as "transcending time and space." However, if it is specified that they "transcend space and time" in the sense that they exist on some higher level of reality that is outright superior to a spacetime continuum in nature, then they should be put at Low 1-C, assuming the continuum in question is one comprised of four dimensions."
-Tiering System FAQ
This part of the FAQ is fullfilled by the other points, in our own set theory standards,
you essentially need an higher level of infinity beyond it, not simply just transcend space time in the same equation of the other listed paragraphs, likewise, what the FAQ assumes is that, uncountable infinities are needed, not that you can just get a ''higher layer of'' the same dimensionality you are exactly making as a point of reference, similar to how High 3-A is infinitely below Low 2-C.
How is "space between dimensions" vague given what we know? It doesn't just make up the space between SOME dimensions or connect them through a thin tunnel. Even Effi said that it outright contains universes in the last thread.
If it just contains universes within itself, it wouldn't qualify for a listed infinity above it, you can still contain 4-D spaces in size and still not exactly exist in a 5-D bulk, good examples? Infinite Zamasu and currently Madoka, they have HDE listed for containing 4-D spaces within their extension, yet they are not exactly 5-D.
So the AD would just be fullfilled with those examples, since by what the evidence you have posted, nothing exactly implies that it transcends space-time in a degree of infinity, an uncountable infinity above a 4-D space would be, for example, if you transcended every single possible extension of those planes(in this case 2-A, since that's the highest possible extension of how 4-D spaces can get in levels of infinity in multiple universal models at once), so with this in mind, you may question.
''If Kirby doesn't have infinite universes, it would still qualify?''
The answer is, if a reality-fiction transcendence isn't implied to exist, then no, and it doesn't fullfill what the standards should meet upon, btw.
Transcend space-time by a degree of one or two higher levels of infinity where an uncountable difference is explicitly made, it would qualify for Low 1-C period, assuming the real coordinate spaces would have to be considered in this equation, that's what the FAQ is trying to make implicit when it uses the other equation of higher dimensional planes, a previous mentioned dimensionality still contains other extensions to be transcended in order to reach such kind of levels simutaneously.
This is simply similar to how a 3-D human would perceive a 2-D axis, no matter how high the axis expand, it will not form a 3-dimensional cube unless something is added in the equation to exactly form it.
Also, to give a little compliment, a bulk space is unbound by something such as infinite extensions of space and infinite extensions of time, I showed the Interstellar example to showcase what I'm trying to exactly talk about.