In a recent Facebook discussion, I had a non-Catholic say this to me:

“If a person, without aid of the internet, volumes and volumes of catechisms and church lore, or any preconceived church traditions picked up a complete Bible, they wouldn’t be able to come up with half the tenants of Catholicism.  

Purgatory in particular. Mary “adoration” on Catholic levels either. Certainly not the immaculate conception of Mary.” 

Let's put it like this: If a person, a complete Tabula Rasa with NO preconceived notions either Protestant or Catholic, were to pick up the Bible and read it, there is a far, far more likelihood that they would end up Catholic than Protestant.

Let's presume that by reading the Bible we mean that the person started in Genesis and ended in Revelation. He would then have the Old Testament as a guide to what he was going to see in the New Testament. Included in that would be that when Jesus established a Church,  He appointed one man as His Chief Steward (the meaning of the keys to the Kingdom... an Old Testament concept). He would see Jesus appoint others to assist him in that task. He would see Jesus ordain and empower those men even before the Day of Pentecost (John 20) and even them give them the ability to forgive sins or not. He would also see that the Lord instituted a sacrament at the Last Supper in fulfillment of what He had told the Apostles in John 6:53.

After all, without any traditions to tell him that those verses don't mean what they say he'd have no reason not to take them at their face value.

Then he'd move on to the history of the Early Church that began in Acts. He see the first homily delivered by Saint Peter in which he says that to be saved one must repent and be baptized. Later he'd read in Saint Peter's epistle that Baptism is indeed required for salvation backing up his words on Pentecost. He'd have no tradition to tell him that Peter didn't mean that.

He'd also see the beginning of Apostolic Succession in the choice to replace Judas and then see it practiced and instructed all through the writing of Saint Paul.

Then in Revelation he'd read in Chapter 11 and 12 about the Ark of God being seen in the Temple in Heaven and that Ark being a woman. He'd have no trouble identifying her because he'd have the Old Testament concept of the Queen Mother as a reference as well as the identity of her Child based on the OT prophecies about Messiah ("rule all nations with a rod of iron"). He'd have no doubt that the Woman is Mary because he'd have no traditions to tell him otherwise.

Finally, he'd have no idea that the men chosen to follow on after the Apostles were untrustworthy and corrupted the Faith... which wouldn't be restored until 1517... without traditions to tell him that. He'd read how those men passed on what they had been taught in the documents which they left behind. He'd find out that the Church didn't disappear but fulfilled (and fulfills today) the commission given them by the Lord.

No, there is far, far more chance such a blank slate reading the Bible would end up Catholic than Protestant. Only man-made traditions contradict what he'd learn there.

The remainder of the dogmas you outline come under the authority of the Church (which authority we've already established with your Tabula Rasa) and, like many key doctrines to which I certain you subscribe, they were developed over a period of time AFTER 100 AD.