I have no idea what relationship you think this has to the proof presented.
Because you force without notion
a,b,c construction (Transitive property) on
a,b construction (not the Transitive property).
Z < h < Y was a fact deduced from the fact h was selected from the interval (Z,Y)
Let us take the interval [X,Y] (X<Y).
If you are talking about [Z,Y] (Z<Y) it is clear that Z of [Z,Y] is not the immediate predecessor of Y exactly as X of [X,Y] is not the immediate predecessor of Y.
Since [X,Y] or [Z,Y] are intervals of
the all members between X and Y or Z and Y, there is an immediate predecessor to Y.
Standard Math cannot explicitly define it and cannot explicitly disprove its existence because if [Z,Y] (Z<Y) is used, then Z is not the immediate predecessor of Y.
This is exactly my claim, Standard Math has no ability to explicitly define or disprove the existence of the immediate predecessor of Y, even if its existence must be true because [X,Y] or [Z,Y] are intervals of
the all members between X and Y or Z and Y.
We are in the same state of Godel's incompleteness theorems, where things must be true but cannot be proved or disproved within the deductive framework that deals with the non-finite.