Is Genesis 1 structured so that there is a general category and then with what will fill it, which would be a type of Hebrew poem of parallel ideas? In this case day one (light), would relate to day four (sun, moon, and stars) while day two (sea and sky) would relate to day five (birds and sea creatures) and day three (the land & vegetation) with day six (animals and humanity). Does this indicate that it is a type of creation poem or song?
Not poetry, but Prologue
Gordon J. Wenham notes in The Word Biblical Commentary Vol. 1: Genesis 1-15 on page 46
...[Genesis 1:1–2:3] stands apart from the narratives that follow in style and content and makes it an overture to the whole work.
On page 50 he continues:
Extrabiblical creation stories from the ancient Near East are usually poetic, but Gen 1 is not typical Hebrew poetry. Indeed, some writers endeavoring to underline that Gen 1 is pure priestly theology insist that it is not poetry at all. There is no "hymnic element in the language" (von Rad, 47). On the other hand, Gen 1 is not normal Hebrew prose either; its syntax is distinctively different from narrative prose. Cassuto (1:11 ), Loretz (1975) and Kselman (1978) have all pointed to poetic bicola or tricola in Gen 1, while admitting that most of the material is prose. It is possible that these poetic fragments go back to an earlier form of the creation account, though, as Cassuto observes, "it is simpler to suppose … the special importance of the subject led to an exaltation of style approaching the level of poetry" (1:11).
Gen 1 is unique in the Old Testament. It invites comparison with the psalms that praise God‘s work in creation (e.g., 8, 136, 148) or with passages such as Prov 8:22–31 or Job 38 that reflect on the mystery of God‘s creativity. It is indeed a great hymn, setting out majestically the omnipotence of the creator, but it surpasses these other passages in the scope and comprehensiveness of vision. In that it is elevated prose, not pure poetry, it seems unlikely that it was used as a song of praise as the psalms were. Rather, in its present form it is a careful literary composition introducing the succeeding narratives.
And indeed, scholars like McBride1 and Waltke2 also regard Genesis 1:1-2:3 as prologue and The opening prologue of Genesis has been compared to the opening prologue of John by several scholars. Subsequently, it is pretty clear that this writing was intended to act as a prologue or overture to the book of Genesis.
Correspondence of days is a framework
While the correspondence of days is present in the structure of Genesis 1, this represents a literary framework, but it does not equate to poetry itself. There are some poetry-like elements within the text however. Whenham notes some of these on page 50 of his commentary:
1:1–2:3 form the first section of Genesis; the second starts with 2:4. 2:1–3 echoes 1:1 by introducing the same phrases but in reverse order: "he created," "God," "heavens and earth" reappear as "heavens and earth" (2:1) "God" (2:2), "created" (2:3). This chiastic pattern brings the section to a neat close which is reinforced by the inclusion "God created" linking 1:1 and 2:3.
The correspondence of the first paragraph, 1:1–2, with 2:1–3 is underlined by the number of Hebrew words in both being multiples of 7. 1:1 consists of 7 words, 1:2 of 14 (7 x 2) words, 2:1–3 of 35 (7 x 5) words. The number seven dominates this opening chapter in a strange way, not only in the number of words in a particular section but in the number of times a specific word or phrase recurs. For example, "God" is mentioned 35 times, "earth" 21 times, "heaven/firmament" 21 times, while the phrases "and it was so" and "God saw that it was good" occur 7 times.
Genesis 1:1 is almost, but not quite a poem or hymn. As such it rises to the level elevated or high prose and acts as a prologue to the book of Genesis. It also repeatedly invites polemic comparison to other creation myths in Mesopotamia.
1 Dean McBride Jr. "Divine Protocol: Genesis 1:1-2:3 as Prologue to the Pentateuch"
2 Bruce K. Waltke Genesis: A Commentary
As the question recognises, Hebrew poetry is very different from Western poetry and thus difficult to recognise initially. We have to look for parallel ideas, rather than rhyme and rhythm. Francis S. Collins (The Language of God: A Scientist Presents Evidence for Belief, page 140) says, "There is no question that this is a powerful and poetic narrative recounting the story of God's creative actions."
Jeff A. Benner ('Poetry in the Hebrew Bible') finds multiple levels of poetry in the first creation story (Genesis 1:1-2:3). First, Benner defines a chiastic structure for this passage, although I would regard it as a parallel structure (one in which the second set is not reversed). Either way, this is a form of poetry common to ancient Hebrew and Greek:
A. Elohiym filled the sky and the land because it was empty and it was all in chaos so the wind of Elohiym settled upon the water (1:1 to 1:2)
A1. Day 1 - Elohiym separates (1:3 to 1:5, Day one)
A2. Day 2 - Elohiym separates (1:6 to 1:8, Day two)
A3. Day 3 - Elohiym separates(1:9 to 1:13, Day three
b. Plants spring up from the land
B1. Day 4 - Elohiym fills (1:14 to 1:19, Day four)
a. the light with the sun
b. the dark with the moon
B2. Day 5 - Elohiym fills (1:20 to 1:23, Day five)
a. fills the water with fish
b. fills the sky with birds
B3. Day 6 - Elohiym fills (1:24 to 1:31, Day six)
a. the land with animals and man
b. Plants are given as food
B. Elohiym Finishes his separating and filling of the sky and the land and respects the seventh day because in it he did his occupation (2:1 to 2:3, Day seven)
At another level, Benner says when we read Genesis chapter one we usually see only one story there, but there are actually many stories. Important to his explanation is that the Hebrew word bara is better translated as 'fatten' or 'fill'. His poetic translation of chapter 1 can be read in full here, but the following is an extract:
Genesis 1:1-2: (Filling the Void) In the beginning the Mighty One filled the skies and the land because the world existed devoid and void. A chaotic void was over the face of the deep then the creative breath of the Mighty One hovered over the face of the water.
Poetry is so commonly used in the Old Testament that we should not conclude this belongs to a particular genre of 'creation poem or song'.
The answer is that this is historical, rather than poetic. The only reason people try to make Gen. 1:1-2:4a poetic is to try to justify their belief of evolution over special creation. If we were to take Dick Harfield's example above, the consensus would be that days one and four would be prominent as they would be the first on the list in each of their respective accounts (forming vs. filling). That would do irreparable damage to God as the highlight of God's creation is light (sun, moon, and stars).
Second, if the focus is "that" God created and not "how" God created, then why would God waste an entire chapter when it could have been summed up in v.1? He could have stated 1:1, then moved to 2:4b with no literary issues. So if there is any literary genre taking place, a parenthetic would be the best explanation because there was something between his assertion in v.1 to his summary of 2:4b. However, synonymous parallelism is not the only poetic device the evolutionary creationist argues for.
Other scholars believe that this is chiastic as opposed to synonymous parallelism to defend evolutionary creation, but that again emphasizes the third and fourth days, which are not even parallel to each other. The point is that one group says it is one type of parallelism, while another of the same belief believes it is chiasm. It can't be both. So how can one know for sure?
Fourth, there is nothing to suggest that Gen. 1:1 is not directly tied to Gen. 1:2 as in, Day 1 was not just light, but the heavens and the earth also. If that is the case, then it shoots a major hole in the parallelism theory, because evolutionary creationists have to force Gen. 1:1 into the mix, and that does not coincide with Day 4.
The rule of literariness is simply this: If the literal sense make sense, then there is no other sense." (Dr. Howard Hendricks, ). God is the God of the miraculous. He is not bound to natural law. The miraculous is supernatural. And if there was any literariness taking place in the Genesis account, the best option would be a crescendo, because man is the pinnacle, the highlight of God's creation. It is only man that was created in His image. It was man He created the whole world to know.
And finally, to those who would argue that the Bible is a theological, rather than a scientific book, the you have a real theological connundrum with a number of passages that declare a baby as a living being in the womb (not just a fetus until it is viable as science declares): “Truly children are a gift from the Lord; the fruit of the womb is a reward” (Psalm 127:3)
“You knit me in my mother’s womb . . . nor was my frame unknown to you when I was made in secret” (Psalm 139:13,15)
“You have been my guide since I was first formed . . . from my mother’s womb you are my God” (Psalm 22:10-11).
“God… from my mother’s womb had set me apart and called me through his grace” (St. Paul to the Galatians 1:15).
The Bible is both scientific and theological. It is for these reasons that the Genesis account should be taken literally instead of figuratively.