Modeling the Universe as an "All-Encompassing Everything" gives rise to a Universe that is Absolutely Infinite. Starting with "Everything" gives rise to a model that is inherently boundless and limitless - if for no other reason that there is nothing outside of this Inherent Wholeness that might be used to measure it.
Due to its inherent boundless, limitless nature, this model indicates that the Universe might exhibit some very unusual properties. Since the Universe is "One Thing" it can technically be considered a closed system. However, since this "One Thing" is inherently limitless, or truly Infinite, it is reasonable to surmise that it functions very much as an open system.
When viewed in this light, the Universe as a Whole could be considered "openly closed" or "closedly open" - ideas which make very little sense within the conceptual framework of the English language. This initial state of Wholeness is practically impossible to describe - if for no other reason that language tends to work through contrast and comparison.
Beginning with Everything has certain advantages to many modern models. First and foremost, it does away with the idea that the physical universe (small "u") could be expanding into "nothing". The Geometric model that I work with embraces the rules of logic in the sense that "nothing" is nothing — not even space — and therefore cannot possibly exist.
Within the Geometric model of the Universe, the physical world (small "universe") is expanding within the limitless boundlessness of the All-Encompassing Everything. This would make the Big Bang more of a Big Ripple running through the pure potential of the plenum.
Under this model space represents a fullness of pure potential' — a plenum in the classical sense. This model integrates the very-old Platonic idea of a plenum with the very-new idea (as articulated by physicist David Bohm) that the emptiness of space is actually full of energy.