Again, saying "they worshiped the sun, moon, and stars" could describe just about any form of polytheism, and nothing in the passage you quoted reveals any kind of special knowledge about the religion practiced by Abraham.
The passage I linked speaks exactly about the findings when excavating the land Abraham lived on. It has various links at the bottom which you can also visit to see. At the end of the day, the Qur'an claimed that Abraham worshiped the Sun, Moon and Planetary Gods. If Muhammad had written the book, he would've more likely copied the Bible's vague description avoid future findings that would prove him incorrect. On the contrary, the findings only prove the Qur'an to be correct.
Clearly, it's claiming here that the mistaken Christian belief in the Trinity includes Mary as part of it.
The verse I quoted said stop saying trinity, it does not explain who is part of the trinity. The next verse:
"O Jesus the son of Mary! Didst thou say unto men, 'Take me and my mother for two gods beside Allah'?" He will say: "Glory to Thee! Never could I say what I had no right (to say).
Is not immediately after but is in another chapter with a different dialogue that is not talking about the trinity.
Veneration of Mary and the saints is different than worship. Any Catholic here would be more than willing to explain that to you. Nobody actually considers her to be "divine" in the same way as the Father, Son, or Holy Spirit.
They worship Mary and that is a form of Idolatry in the eyes of God. They pray to her and believe she is the mother of God, exactly what idolatry is. God does not care what you mean by it, associating anything with him is forbidden. Saying 3 in 1 means associating partners to him, not matter how you get around the fact the trinity still means one God.
Yes, but they didn't actually mean that in the same way that Christians do about Jesus.
Still a form of Idolatry.
This mistakenly conflates the Christian idea of "son of God" with the Jewish one, and then calls the Jews polytheists based on that.
Well some Jews did believe he was the son of God, and just because you see it as different idea, it's really not in the eyes of God and is the same thing, idolatry.