The Heisenberg Uncertainty principle falls out of the mathematics of waves and fourier transforms.
Incorrect. The Uncertainty Principle was nothing more than Heisenberg's epiphany, i.e. simple common sense, that any measurement at the quantum level will itself affect the phenomena being measured. There was no math involved.
Thereafter, the math involved in accounting for the Uncertainty Principle was derived from math. It's amazing how that works.
Is there anything particularly philosophical about 2+2=4?
It turns out that there is. Mathematicians are obligated to ask "Does two plus two always equal four, or does it only equal four most of the time? Are there any examples whereby adding two of something to two more of that something does not equal four?" ... i.e. mathematicians require proofs.
Hence, there are actually two philosophical parts that must both be resolved. First, what is a number? Second, what is "plus" (i.e. operation of addition)? The good news is that long ago, mathematics defined numbers and the operation of addition, and thus showed that 2+2 always equals 4, and the commutative and associative properties of addition were proven as well. Then, building on that success, the operation of subtraction was defined. Thereafter, multiplication was defined based upon the same definitions of numbers and addition, and multiplication was also shown to be commutative and associative. Then division, using the definition of subtraction. Then derivatives, using the definition of division. Then integrals, using everything aforementioned.
As it goes in math, things only need to be proven once. This is why children get to start directly at 2+2=4 and don't ever have to research any of what I wrote above because it has already been proven and no one needs to reinvent the wheel.
... as a result, we have the luxury of asking the very question you asked:
Does it require some special feature of the eternal universe or is it effectively tautological?
Answer: In mathematics, numbers and mathematical operations have been defined as how we humans logically view nature and how it works.
2+2=4 is only a convention, a construct of the base 10 numeric system we have agreed to use. It's not an eternal truth.
In mathematics, numbers have been defined independently of any labels (and thus independently of any "base"). That you are accustomed to the symbol "2" meaning "two" does not make the symbol the number. In Afghansitan, the "٢" is commonly used as the symbol for "two". In mathematics, only the number "one", or "uno", or "eins" or "یک" or "Едно" ... or whatever your particular language uses for "one" is defined as a labeled number. Thereafter, the definition/theory holds that every number has a successor that is also a number. This forms the natural numbers, and also establishes the methodology for proof by induction, i.e. you show that a relationship holds for a specific number (normally for the number one), and then show that if the relationship holds for a number, that it necessarily holds for its successor as well. That proves that the relationship holds for all numbers.
Mathematicians like to ask the trick question "If you add the number zero to the natural numbers to make the set of whole numbers, do you now have one more number than you previously had, or do you still have exactly the same number of numbers?" The answer is that you have exactly the same number, and you can prove it by simply shifting the symbols, i.e. label zero as "1", label one as "2", two as "3", and so forth.
A quantum flux that created the universe could seemingly only have happened if the Heisenberg uncertainty principle was in place and preceded it.
This is gibberish. The Heisenberg Uncertainty principle involves observation affecting the quantum phenomena being observed. The universe was not waiting for an observer to affect it into existence. In fact, that doesn't even make any sense.
Which begs the question, why did the Heisenberg uncertainty principle exist before creation?
I don't think Heisenberg existed before creation, much less the principle he expressed.
You can't have quantum flux without the principle underlying it in place already. It just a chicken before the egg question
Gibberish.
I don't see 2+2=4 representing a real natural relationship in the universe.
Mathematicians disagree with you. That's OK, though. They could be wrong.
It is a convention based on Hindu-Arabic base 10 numerals we have agreed to use.
Nope. Mathematics defines numbers and mathematical operations to represent real natural relationships in the universe.
In and of itself it doesn't represent any spatial or temporal relationships.
You might notice that if you add two of something to two of that same something, the result is always four of that something.
What else is there about the Heisenberg Uncertainty Principle that makes it different from 2+2=4?
The lack of certainty. You should have seen that coming. Math is a
closed functional system in which you can prove/predict that adding two to two will equal four in all cases. Science is an
open functional system and Heisenberg expressed that you cannot know/predict what will happen (at the quantum level) until you observe it, and even then you don't know exactly what you observed because your observation itself screwed with the event.