Bear with me, as I am new to the Catholic faith, and Mary has been difficult for me to understand, since, growing up Protestant, she was not on my radar…also forgive me, if this has all been mentioned, I didn’t have time to read the entire thread.
I want to address veneration first. Veneration is giving honor to someone, and this concept is actually quite biblical. Paul many times exhorts, (even uses strong language like the words “must imitate”) the church to imitate him personally (1 Thess. 1:6, 2 Thess. 3:6, Phil 3:17-20, 1 Corin 11:1). Imitation is certainly a form of honoring someone. We have an example in the Saints, including Mary, to follow, a sure way to become holy, by imitating their lives. And being holy, after all is what we were made to do (1 Peter talks about the importance of holiness, for example). Paul says we should give honor to others-Romans 2:10 says, “there will be glory, honor, and peace for everyone who does good”. 1 Corinthians 12, in the section on the unity of the body of Christ says that God constructed “the body as to give greater honor to a part that is without it…if one part is honored, all parts share its joy”. In Galations 6:10 Paul tells us: “let us do good to all, but especially to those who belong to the family of faith”. Certainly Mary belongs to the family of faith! 1 Thess. 1:6 even goes on to point out that the purpose of imitating the mature in faith is to then become models for others, so they may imitate us!
I think one of the keys to the Mary issue and veneration, praying to saints, etc, is understanding the idea of there being one body of Christ, that is the Church. We are not a body here on earth and a separate body in heaven, with nothing to do with one another. God designed it so that, "the eye cannot say to the hand, I do not need you, nor again the head to the feet, I do not need you. (1 Corin 12:12 and following). There are many other passages on this reality of unity among the body–Romans 12:4-5, Eph 4:1-6, Colossians 3:15 to name a few.
If we are all one body, then it follows that we all need each other. The saints are not dead-they are alive (Mark 12:26-27) and in the presence of God. Hebrews 12:1 indicates that we are surrounded by a great cloud of witnesses. Who are they? Well, if you read chapter eleven, we see that these witnesses who are watching our lives unfold are none other than the saints-Abraham, Moses, Gideon, David and others-a great cloud of them!
We also know that the body is exhorted to pray for one another. Romans 15:30, Colosians 4:3, 2 Thess 3:1, Eph 6:18-19 all exhort us to pray for one another. So it makes sense that the saints, as members of the body of Christ, may pray for us, who are also members of his body. Also, we do see a picture of this in Revelation 5:8.
The key to the Queen of Heaven bit is understanding the ancient Jewish concept of the queen being the mother of the King, rather than the wife. I have to be honest and say, I haven’t read a lot on this, but I know the example used is that of Bathsheeba and her son Solomon. Try giving the story a look in 1 Kings 2. Also, we see Mary crowned as a queen in Rev12:1.
Immaculate conception: for this, it’s critical to understand the concept of Mary as the New Ark of the Covenant. Look at the parralels in the stories-the ark carried in it bread (Jesus is the Bread of Life, a shepherd’s staff (Jesus is the good shepherd), and the Law (Jesus is the Word made flesh). The real presence of God was thought to be inside the ark, just as the real presence of God, that is, Jesus, dwelt in Mary. There are even more parralels if you read the two stories side by side: David leaps before the Ark, John the Baptist leaps in Elizabeth’s womb. David asks how it is that the Ark would come to him, Elizabeth asks how the Mother of her Lord would come to her. The Ark remained in the house for three months, Mary remained with Elizabeth three months. The Ark set out for Judah, Mary set out for Judea (aka Judah). We also see the Ark in heaven in Rev 11. You can check these passages out in 2 Samuel 6 and Luke 1.

and when you do, notice what happens to Uzzah when he reaches out to touch the Ark. (He dies). The Ark was so holy, no one could even touch it. So if Mary is the New Ark, it would follow that she be holy. And she is: the angel tells her that she is full of grace and highly favored in God’s sight. Mary herself says the Lord has done great things for her.
Co-redemptress: I’m certain someone will correct me if i am wrong, but I do not think she has been called co-redemptress officially in the catechism (or as dogma). Nevertheless we must realize that if she is at some point officially given the title, it only applies in as much as we are all mediators and “redeemers” due to Christ who lives in us. Mary has a special role in that through her “yes” Christ came in the world, but the truth is, we are all mediators in the sense that we can pray and involve ourselves in helping people come to Christ, who is the only mediator between the Father and man. 1 Corin 9:22, Jude 1:22-23, James 5:19-20.
Yes, there have been some who have not understood Mary’s role properly-both by ignoring her or by making her a god. Both should be corrected. But I hope I have given you some things to chew on and ponder regarding Mary. I am still pondering many of these mysteries myself. God bless you, OP, I will say a prayer for you today!