1. If an allegorical system of interpretation is applied to the creation story, that is 6 days is billions of years, how about the rest of the scripture?
2. God saw all that He had made, and it was very good. And there was evening, and there was morning— the sixth day. (Genesis 1:31), what is the correct and actual interpretation of this?
3. Any cross-references in the Scripture is the word “day” used to designate billions of years.
4. Why did God have to take a billions year to create the Universe? What specific age did scripture talk about?
5. Where is the story of that hypothetical billions years of activities of may be pre-Adamic races?
6. Where are sound exegetic arguments for “Yom” as epoch and where in the text of Genesis 2 and following is the transition from epoch-long days to 24-hour days?
For question 3) Yom is translated in the Hebrew Bible in the NIV in the following ways:
1181 times as “day” (but with several different connotations of the word, some not being literal. ex Isaiah 4:2 In that day, the Branch
of the Lord will be beautiful)
67 times as “time”
30 times as “today”
18 times as “forever”
10 times as “continuously”
6 times as “age”
4 times as “life”
2 times as “perpetually”]
For example, in Genesis 2:4 yom is translated as “when.” The use of yom in Hebrew is not like our use of day in English. We say “In my day, people took school seriously.” Is this a reference to a particular day? No! Yom is often not a literal day in Hebrew.
OECs do not take the creation story allegorically. They take the days metaphorically, not allegorically, which is a very different thing. We take many, many things metaphorically, including the Bible teacher you mention. In Isaiah 59:2 it says that God’s arm is not too short to save. Does God have a literal arm? Of course not! Whether or not we take something metaphorically is determined, not by some particular rule but by a case-by-case common sense basis.
Is the thousand years of Revelation 20 a literal thousand years or a complete but rather long period of time? I do not know.
Are the “days” of Genesis 1 literal days or not? Debatable.
What is the “correct and actual interpretation” of the days? I do not know. You will have to ask God. Most commentators believe that there is at least some metaphorical aspect to the Genesis account because that is normal for Near Eastern literature in that time frame.
Why did God use vast periods of time over which to create the universe? I do not know. You will have to ask him. I do know this: God is not limited by time as we are. God exists outside of time and for him the idea of waiting for a long time does not exist. Like God said to Moses, I AM. To God, whether it took a few weeks or one instant or a billion years is immaterial.
Why does the Bible not say billions of years? Probably the Near Eastern person living 2000 BC would not be able to comprehend this. It was unnecessary information. Why did he not tell them about galaxies and trilobites, and bacteria and gravity and atoms? Why should he tell them these things? The Genesis account is theological, not scientific. We are trying to apply a modern question to an ancient audience
I am not sure what you are talking about with the “pre-Adamic race.” The Bible does not mention a pre-Adamic race. It also does not absolutely rule out a pre-Adamic race. There are an infinite number of things the Bible does not talk about. The Bible does not talk about evolution. That does not mean that it did not happen. The Bible does not talk about people living in South America, but they did.
For question #6, already in Genesis 2:4 we see yom translated as “when.” Yom is translated as day (24 hours) then as age, then as time, then as day (but not a literal day) then as continuously, then as literal day then…. There is no pattern. It is always translated according to context. The Old Testament talks about the “day of the Lord” dozens of times. NEVER is the “day of the Lord” a single day. Ever! This is not so much exegesis as it is hermeneutics. Your friend is looking for a simplistic answer where there is none.