Regarding terminology for what comprises "the" universe vs "our" universe, etc., I doubt we could get agreement on "universe" as all we can observe vs "superverse" for anything postulated beyond what we can observe.
We already have "observable universe" as a subset of the whole "universe", and the position by some that there is nothing outside the universe by definition of the word "universe". It becomes a sort of a conceptual boundary problem, with no real agreement on the boundary.
For instance, once something that is clearly in our universe goes into a black hole, is it still in our universe? Why? Is it because our universe surrounds it (at least in the 3 dimensions we perceive)? Even though we can no longer observe whatever is in it? Or, has it left our universe? It still has some effect on our universe in the way of gravity and frame dragging, so is that reason to say it is in our "universe" instead of becoming part of the "superverse"? And, what about "dark matter" that may or may not be observable in our universe, but seems to have effects on our observations? If that were in an unperceived dimension that we cannot observe, but it still affects us with gravitation and frame dragging, is it inside or outside our "universe" or the "superverse"?
I think I understand your concept, but I don't think it is going to move us forward in the discussion, because the boundary is too theoretical, and there are too many competing theories.
I liked your earlier effort at clarifying the definitions using "observable" universe, etc., but I don't remember where that is posted.