That is a deceptive question. Originally you have used the word "conceived". Now you drop the word "conceived" and switch your approach. Mary did not "conceive" (bring into being) the second person of the trinity. Yet you have consistently tried to get me to agree that Mary conceived the second person of the trinity. She did not. Therefore she can not be considered the "mother" of God. She can, as the Holy Spirit inspired the writers to write be considered the mother of Jesus because she did conceive (bring into being) the man Jesus. I'll simply leave you now to the torment of trying to figure that out.
>>This is why I ask: “Is ‘that holy thing which shall be born of’ Mary and ‘shall be called the Son of God’ the same God that is the second person of the Trinity.<<
That is a deceptive question.
I do not mean to be deceptive. But I now see where we are focusing on two different things. You on conceiving and I on giving birth.
I will concede your point on conceiving. But Mary did give birth to the second person of the Trinity in Christ Jesus. And Mary raised the second person of the Trinity in Jesus. These are both attributes of a mother. So how can it be said that Mary is not the mother of the second person of the Trinity?
Again, any teachings you can share with me that explains this would be appreciated.