No, that is modalism.
David called God the Lord--all caps LORD, meaning YHWH--his SHEPHERD. Jesus said HE is the good shepherd. 1 Peter 5 has Peter calling Jesus the "chief shepherd."
No, if you are talking about Psalm 110:1 the word for Lord is not Yahweh in the case of Jesus but Adon and not Adonay but Adon and the capitals are added by the Translators.
But Jesus DID call Himself by God's holy covenant Name--"Before Abraham was, I AM."
Not hardly because Jesus was speaking of Abraham seeing his day in a vision and not seeing him personally and it was only upon their twisting his words when they said "you are not yet 50 years old and you have seen Abraham" that Jesus said this and he was still speaking of God's vision that he gave unto Abraham when he said it also.
In other words, in God's vision, foreknowledge and plan, "before Abraham was, Jesus was foreordained to be standing in front of them in the first person present tense".
Kind of like when in Jeremiah 1:5 God told Jeremiah, before I formed you in the womb I knew you (intimately), for it is the same word used of a husband knowing his wife sexually.
See also Paul's words in Romans 8:29, for Jesus the man was the very model that God predestined all others who would be his elect sons, to be conformed to the image of and that included Abraham also, and thus before Abraham was in God's vision and plan, Jesus is and thus he is called the firstborn because of that.
But man can--hence, why Jesus became Incarnate AS a man, so He was born of a woman, born under the Law, to redeem us from the curse of the Law, by becoming a curse for us. He kept the Law perfectly AS a man. But He never ceased to be God even in His incarnation, but limited His power and glory in His humbled state--He "who was rich became poor, for our sakes."
The only thing that was incarnated was a copy into flesh of the Logos that was God and remained God in God's nature.
Hebrews 1:3 is actually revealing the same thing also, for when it says in the translations "and the express image of his person" that word for "express image" is the Greek word "charakter" and which was used to speak of an image from one substance being pressed and copied into another substance.
It was used to speak of the images of the emperors of Rome copied and pressed into the coins or the image on a signet ring pressed into a wax seal, but it never referred to anything that was not copied, for the word is not used that way at all.
Also anytime you want to discuss Philippians 2:5-8, let me know, for I can show you by the very Greek words used by Paul and the context, that Paul wasn't even speaking of the nature or ontology of Jesus at all but only his God given authority and it was that which he humbled himself in and not any attributes as being God, for Paul was never saying that he was God.
For starters that word "huparchon" which is translated as "being or existing" in verse 6, is used better than 60 times in the NT and it means "to begin quietly under" and it is never used of anything that never had a beginning either.
For this reason it is also only used of God twice, once in Acts 17:24 "God who created the world, is (huparchon) Lord of heaven and earth" and do notice that God only began to exist (huparchon) as the Lord of heaven and earth after he created it first and that is why Paul speaks of him creating it first in the verse.
Then it is used again by Paul in Acts 17:27 when he says "he (God) is (huparchon) not far from any of us" and notice again, that he only began to be exist not far from any of us after he first created us.
So you see that the word is only ever used of things that began and it is never used of God to speak of his purely eternal existence and that is also why Paul used in in Philippians 2:6 for Jesus, because he had a beginning of his existence and did not exist eternally like your churches are falsely teaching.
Then you have that word "morphe" translated "form" and which makes no sense at all for Paul to use if he was truly saying that Jesus pre existed as God and then became a man, for if he wanted to say that, he certainly wouldn't have used the word "morphe" at all and wouldn't have needed to either.
For the word "morphe" doesn't mean nature as in actual ontology or substance but only the characteristics or appearance of a substance instead and I can also prove this by how the word is used in other places of the NT.
Notice also, Jesus explained why in John 14:8-10 when they saw him they saw the Father also and he never said that it was because he also was God but rather this is what he said in verse 10, "the words that I speak unto you, I speak not of myself, it is the Father who dwells within me, he is doing the works".
So we see here why and in what way Paul is describing Jesus as beginning in the form of God, it was because God as the Father was dwelling within him and revealing himself through Jesus by the works that he was doing and Jesus even told us this more than once also.
Notice also in Acts 2:22, that Peter says the same exact thing, that the miracles were not done by Jesus but by the Father who was dwelling within him and revealing himself through the miracles done through Christ.
Acts 2:22 “Fellow Israelites, listen to this: Jesus of Nazareth was a man accredited by God to you by miracles, wonders and signs, which God did among you through him, as you yourselves know.
Anyhow, this is a good start, and whenever you want to go further, let me know, for I would be glad to discuss this with you any time.