YOU: in the last two paragraphs you quoted above you can see the author undoing what he hoped to define as a distinction between the Trinity and Pantheism. The Essence of God is being as much of the God-ness thing as anything else of God's. Or to apply the 'essence' analogy to Jesus or to the Holy Spirit, what is being claimed in the Trinity is that these are God because they are filled with the God thing, so by that standard the 'Essence' of God which has just been admitted as pervading creation/universe should also be fully God....and by extension of logic creation then becomes pantheistic.
ME: I think you're stretching the logic again, inverting it, and almost begging the question. You're claiming creation becomes pantheistic (God is "in" everything) because the God thing fills the Trinity and Jesus and is everywhere because God is omnipresent, but I see three weaknesses here. First, the church is decidedly non-pantheisitic; God's omnipresence does not mean He is IN everything, but EVERYWHERE.
"God is everywhere, say theologians and philosophers, by his power, his essence, and his knowledge. By his infinite power he is everywhere because he gives existence to all things. He is everywhere by his essence because what God is (his essence) isn't separable from what he can do (his power). God is everywhere by his knowledge because he knows all things at all times." http://www.catholic.com/thisrock/quickquestions/keyword/prayer/page11
Secondly, your statement: "to apply the 'essence' analogy to Jesus or to the Holy Spirit, what is being claimed in the Trinity is that these are God because they are filled with the God thing," is an inaccurate description of the Trinity. With respect to immanent Trinity, the one triune God is not God because He is FILLED with the God thing, or essence, as though it were some container. It IS the God thing. Neither are the three Persons filled with the God thing. Nor do each of the Persons fill each other. They are the consubstantial essence, inseparably, because each is God, so there can't be a proper analogy with pantheism where God is seen as filling something and being IN all things.
Third, as mentioned, the hypostatic nature of Christ, that He was/is God-man does not mean that the God part filled the creature flesh part like the pantheistic God who is seen to be IN all things.
“If the pivotal assertion of the New Testament, “The Word was made flesh” (Jn 1.14), means anything, it signifies that two, the divine and the human, became somehow uniquely one in Jesus of Nazareth; that in Him was achieved a union, elsewhere unparalleled of God with man” (ibid., 918)." "The Church believes that Jesus Christ is true God, Son of God made man, the Second person of the Trinity, who took unto Himself a human nature and so exists not only in the divine but also in a human nature: one divine Person in two natures. The man who in His earthly life was known as Jesus of Nazareth was not a human person made one, as Nestorius said, in a unique way of moral unity, with the Person of the Son of God. He was God, Son of the Father, made man for men’s salvation. (ibid., 932) “His human nature, perfect and complete, was not a human person distinct from the Divine person of the Word … it was the human nature of a Divine Person."
Remember, the creature Jesus, the created humanity who was not the Almighty, did not become God because God filled the flesh with the God thing. The Almighty did not insert Himself in the flesh in order to make the flesh God. That is not proper Trinity teaching. So I t