How would Biblical Unitarians answer the questions of Proverbs 30?

As a non-Trinitarian, my answers would be as follows.

1. Who has ascended to heaven and come down?
2. Who has gathered the wind in his fists?
3. Who has wrapped up the waters in a garment?
4. Who has established all the ends of the earth?
5. What is his name?
6. What is his son's name?

1. This is a rhetorical question challenging the listener to suggest any human to have accomplished such a feat. Obviously, Jesus had not yet walked this earth, had not yet ascended to Heaven and returned, as happened later.

2. Again, this is a rhetorical question, invoking thoughts of God's omnipotence.

3. Rhetorical question, as above.

4. Rhetorical question, as above.

5. His name is Yahweh (YHWH).

6. His son's name is also Yahweh (YHWH)--they have the same name.

Textual Support

And Abraham planted a grove in Beersheba, and called there on the name of the LORD (יְהוָ֖ה/Yahweh), the everlasting God (אֵ֥ל/el). (Genesis 21:33, KJV)

And Abraham called the name of that place Jehovahjireh (יְהוָ֣ה-יִרְאֶ֑ה/Yahweh-yireh): as it is said to this day, In the mount of the LORD (יְהוָ֖ה/Yahweh) it shall be seen. (Genesis 22:14, KJV)

¹³And Moses said unto God, Behold, when I come unto the children of Israel, and shall say unto them, The God of your fathers hath sent me unto you; and they shall say to me, What is his name? what shall I say unto them? ¹⁴And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you. ¹⁵And God said moreover unto Moses, Thus shalt thou say unto the children of Israel, the LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations. (Exodus 3:13-15, KJV)

Thou shalt not take the name of the LORD thy God in vain: for the LORD will not hold him guiltless that taketh his name in vain. (Deuteronomy 5:11, KJV)

Hear, O Israel: The LORD our God is one LORD: (Deuteronomy 6:4, KJV)

If in fact God and His Son were both "God" and "Lord", these verses saying there is only one Lord God would be false. According to the Scriptures, we have only one God. Nor is this God said to have multiple personalities. He (not "they") is said to be one, to never change, and to be the great "I AM" (not the we are).

Nowhere in the Old Testament, or even in the entire Bible, are we given "names" for God. The Bible consistently refers to God as having a singular name--just as we see even in the passages that many might like to interpret in other ways, such as in Isaiah 9:6 and in Matthew 28:19. In both of these verses, the "name," in Hebrew and in Greek respectively, is grammatically singular.

According to the Ten Commandments, believing in any other god is a violation of the very first of the Ten. There is, and can be, only one God.

Jews have never been Trinitarian, yet Jesus affirmed that the Jews had the correct understanding of who God is.

²¹Jesus saith unto her, Woman, believe me, the hour cometh, when ye shall neither in this mountain, nor yet at Jerusalem, worship the Father. ²²Ye worship ye know not what: we know what we worship: for salvation is of the Jews. ²³But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him. (John 4:21-23, KJV)

Jesus, the Son, taught that the Father was "the only true God."

¹These words spake Jesus, and lifted up his eyes to heaven, and said, Father, the hour is come; glorify thy Son, that thy Son also may glorify thee: ²As thou hast given him power over all flesh, that he should give eternal life to as many as thou hast given him. ³And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent. (John 17:1-3, KJV)

Jesus was sent by "the only true God," the Father, and in the name of the Father.

I am come in my Father's name, and ye receive me not: if another shall come in his own name, him ye will receive. (John 5:43, KJV)

So, in the New Testament, both the Father and the Son bear the name "Jesus." This name is of paramount importance to us.

¹⁰Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom ye crucified, whom God raised from the dead, even by him doth this man stand here before you whole. ¹¹This is the stone which was set at nought of you builders, which is become the head of the corner. ¹²Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved. (Acts 4:10-12, KJV)

Conclusion

In the Old Testament, the name of both Father and Son is "Yahweh." In the New Testament, the name is "Jesus." The Father is "the only true God," according to God's Son, and is the Son's God just as He is to be our God. Even after his resurrection, Jesus taught this.

Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God. (John 20:17, KJV)