Is consciousness universal?
Given the rest of your question, universal here presumably means that every bit of matter is conscious. This is committing the same fallacies as the Trinity. Allow me to explain. The idea of the Trinity (in the Christian doctrine) is that the Trinity is one person, God, made of three persons, God the Father, God the Son (Jesus Christ) and God the Holy Spirit. The problem starts when we remember that a person is something which is supposed (in the Christian doctrine) to possess free will. Ah. How does it work? The Trinity has free will and wants to go visit the Eiffel Tower. However, God the Father also has free will and wants to visit the Taj Mahal. Jesus Christ also has free will and wants to visit Jerusalem once more, while God the Holy Spirit just wants to stay put.
With the idea that every bit of matter possess consciousness, we end up with a similarly overegged pudding where there would be an infinite number of consciousness layers for every bit of matter, a sort of Meinongian inflation.
I have just read "Why" by Philip Goff. He proposes that matter consists of conscious entities. Physics based on mathematics tells us what matter does, not what it is.
The crucial point about the brain is that it is a cognitive system. And, this is the only system we actually know that it is conscious. A sandwich presumably is not a cognitive system, and if it possessed consciousness, it would be so thin as to be virtually non-existent. I would say that it is not even measurable, if by that we mean that it could not even answer the question of whether it is conscious.
This has implications for the origin of the universe and its development.
Only if we first established what physical relation there would be between matter and consciousness, which is precisely what we seem unable to do.
It also impacts on our understanding of human consciousness.
I doubt that very much. The subject has been discussed to death for the last 3,000 years and we are barely wiser than Plato. The current literature is systematically confused, as you are yourself, between the informational contents of the mind and the subjective experience of these contents. The former can clearly be reproduced by machine, the latter is as elusive today as it ever was. Confusing these two very different aspects can only lead to the wrong conclusion.
There is the potential for the development of universal values,
This would concern the informational contents of our mind. And I was under the impression that humanity didn't wait for Philip Goff to try and develop universal values. The irony here is that it is precisely the self-interest of each conscious blob of matter who is a legitimate member of humanity which denies the application of those universal values to anyone but themselves.
the first of which is existence itself.
Existence a universal value?! Kant for one would have strongly objected. You really need to exist before you could even think about developing universal values.