Where is the evidence of this non-dual oneness that you are talking about?

There is no time involved to collect evidence.

Looking for evidence of the timeless is a fool's errand.

Ancient saying:  the eagle leaves no tracks.

All these esoteric things you mention cannot be tested as in
scientifically/mathematically tested and therefore cannot be
established as scientific facts.

As if the established scientific facts and scientific proof is some lapis philosophorum which convertssomething into unconditional evidence.

A scientific proof cannot even prove  what it seeks to prove as an absolute truth because whatever it comes up is conditional to the environ in which the scientific proof was attempted to be established.

The actuality of what is, cannot be referred to.

Whatever is referred to, is of mind, of thought.

Science takes time, involves testing and comparison, is of the mind, of thought.

Science involves accumulation and contrast of "facts."

What is, involves no accumulating, is not known in contrast to something else.

Having said that, I also BELIEVE the oneness of creation to be true.
But just because I believe it to be true does not make it a scientific
fact.

What you believe, is not the actual.

It is mind-construct, dependent on a brain to hold it.

When the brain goes, the thought-construct goes.

Yet what is has not gone anywhere, is as is.

These are subjective things which CANNOT be proved as of today
with our current scientific/mathematical methods. It is better to
accept them as beliefs rather than claiming them to be true.
Also, a "belief" is not necessarily false. You mention about non-
separation as a fact, but are not able to prove it. And if it is true
then are you actually manifesting it thusly? Give me one instance of
where and how this non-separation is true and testable to be so.

It never is not the case.

If something could exist in separation from something else, it wouldbe impossible to experience.

The knower would be separate from the known and thus couldn't "contact" it.

Separation/division is a thought-constructed mirage.

And even thought never arises in separation.

As convincing as separation/division is, upon deep investigation, itis mirage - never more real than the belief in it, never actual -always depending on the past to supply images that invoke feelings of existing separately. 

And the images of the past only arise presently, only arise non-separately.