Thank you for your input and expressing your view very clearly. It might surprise you that I agree with much of it.  The major problem it that the verses you are using are conditional blessings under the Mosaic covenant and have no bearing on the unconditional covenant made with Abraham and David.  The verse you quoted from Gal. 4:16  Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.  17  And this I say, that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect. For if the inheritance be of the law, it is no more of promisebut God gave it to Abraham by promise., This does not disannul the covenant He made with Abraham.

Below I have copied two form of ancient covenants

(A)  One type of ancient covenant that serves as a model for certain biblical passages is the royal grant. In this type of covenant, a king or other person in authority rewards a loyal subject by granting him an office, land, exemption from taxes, or the like. In such covenants only the superior party binds himself; conditions are not imposed on the inferior party; they are called covenants of promise or unconditional covenants. The covenants God made with Noah (Genesis 9:8-17), Abraham (Genesis 15:18), and David (2 Samuel 7; 23:5) fit this pattern. In each of these cases, it is God alone who binds himself by a solemn oath to keep the covenant.

(B) The Mosaic covenant (Exodus 24:5... Deuteronomy 5:2  Joshua 23:16) seems to have been modeled on another type of ancient covenant, the political treaty between a powerful king and his weaker vassal. Following the standard form of such treaties, God, the LORD, reminds Israel, thesuzerain, how God has saved it, and Israel in response accepts the covenant stipulations. Israel is promised a blessing for obedience and a curse for breaking the covenant.

There were also three covenants used in the Bible.

# 1  Shoe covenant  used by Boaz in a binding agreement to redeem Ruth.

Ruth 4:7  Now this was the manner in former time in Israel concerning redeeming and concerning changing, for to confirm all things; a man plucked off his shoe, and gave it to his neighbourand this was a testimony in Israel.   Therefore the kinsman said unto Boaz, Buy it for thee. So he drew off his shoe.

# 2   Salt covenant God made with David 2 Chronicles 13:5, Ought ye not to know that the LORD God of Israel gave the kingdom over Israel to David for ever, even to him and to his sons by a covenant of salt?  Salt binds and preserves.

# 3   The Blood Covenant Hebrews 10:29  Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?

This is an unconditional and everlasting covenant make by the blood of our Lord Jesus Christ , and is called the new covenant.  Heb 13:20  Now the God of peace, that brought again from the dead our Lord Jesus, that great shepherd of the sheep, through the blood of the everlasting covenant,

The first blood covenant made in the Bible was an unconditional one with Abraham.  It answers to the covenant "A "above

The blood covenant was used by two people as binding until death. It was the strongest and most binding of all covenants. They would take an animal and kill it. They would divide it in two parts and lay them apart. Each would walk through the parts and shake hands and their part in this covenant. The blood covenant was used by two people as binding until death. When God made this covenant He alone walked through the parts as Abraham slept, but he saw it all.  It was absolutely unconditional and binds God by His own oath.    

God made three unconditional promises to Abraham, and He made an unconditional covenant  to fulfill them. This is the sovereignty of God.

Gen 12:1-3  Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father's house, unto a land that I will shew thee And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing And I will bless them that bless thee, and curse him that curseth theeand in thee shall all families of the earth be blessed.
1--Personal Blessings   "I will bless thee"
2--National  "I will make of thee a great nation"
3--Universal   "All the earth"
His covenant secures these promises.  He has and is fulfilling each of them partially up to the present time, and will complete them in the future.  Talk about the Sovereignty of God, here it is demonstrated.

His covenant is found in  Gen 15:7, And he said unto him, I am the LORD that brought thee out of Ur of the Chaldees, to give thee this land to inherit it.   And he said, Lord GOD, whereby shall I know that I shall inherit it?  And he said unto him, Take me an heifer of three years old, and a she goat of three years old, and a ram of three years old, and a turtledove, and a young pigeon.  And he took unto him all these, and divided them in the midst, and laid each piece one against anotherbut the birds divided he not.

Three living things that died and were divided in the midst.  This is the blood covenant.

11  And when the fowls came down upon the carcases, Abram drove them away.

This act, unknown likely, by Abraham, was to tell the birds that they were not to interfered with this solemn covenant.

12  And when the sun was going down, a deep sleep fell upon Abram; and, lo, an horror of great darkness fell upon him.
13  And he said unto Abram, Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years;
14  And also that nation, whom they shall serve, will I judgeand afterward shall they come out with great substance.
15  And thou shalt go to thy fathers in peace; thou shalt be buried in a good old age.
16  But in the fourth generation they shall come hither againfor the iniquity of the Amorites is not yet full.

His national promise  confirmed by a blood covenant 12:3

17  And it came to pass, that, when the sun went down, and it was dark, behold a smoking furnace, and a burning lamp that passed between those pieces.

The burning lamp (Shechinah glory)  and the  smoking furnace was God passing along through the midst of the pieces.    Abraham had no part at all in this covenant.  He was horrified.

18  In the same day the LORD made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates

Abraham killed the animals and laid them in parts but did not pass through the midst of them. God alone made this coventant and,

God will keep His promises to Israel!