Conspiracy? No, that wouldn't be the word that I'd use. Rivals in competition? Yes.
Each community had their rites and oral traditions that they'd claim from a Apostle or someone who knew the Apostle (the patriarch). Many of those communities were originally of the "Eastern mysteries" style pagans. These claimed special knowledge of god(s) and secret rites that were forbidden to outsiders. As the apostles spread the story of Jesus, these sects would replace their deities with Jesus in worship but retained the idea that they had special, and therefore superior, knowledge of God.
The bulk of Christendom at the time, churches of Peter, Andrew, and Paul shared the same creed and teachings and cooperated as one church. Particularly in being firmly opposed to these Gnostic sects as being in error concerning the faith. But since there was no hierarchy of authority among the churches, they could only warn or try to persuade the others (1 Tim 6:21, St. Justin's "Syntagma", and St. Irenaeus).
Each community would combine or reject doctrine and traditions from the other sects as they wished. Sometimes by adopting a "foreign" tradition they might have to correct or embellish their established doctrine.
About 100 years after the Crucifixion we see individual sects following distinct "schools" of thought: the communities of Valentinus, Basilides, Marcion, Polycarp, Thomas, and John were some of the major groupings.
As the church grew, the factions competed with each other as to who had the "correct" doctrinal faith. By the time Constantine recognized the church in 313 and the Council of Nicaea, the game was pretty much over. The Peter-Paul-Andrew juggernaut, joined by a splinter sect of the Johannines (and their Gospel of John) became the dominant creed.
If you don't have it book marked, let me recommend Early Christian Writings
Sections (in no particular order):
'Signs Gospel',
'Book of Hebrews',
'Gospel of Thomas',
'Gospel of Peter',
'Gospel of the Ebionites',
'Acts of Pilate', and
'Pistis Sophia'
You must have done some serious study on the history of canonical texts. Whatever statements you make in this regard I am inclined to regard as worth consideration. Is there a culminating idea WRT the subject at hand you are attempting to assert?
Where the topic of creationism vs. materialistic evolution is concerned it seems the text of Genesis 1 is a good point of reference. Every biblical text makes statements the hearer will evaluate one way or another, or, as often happens, disregard. After some years of familiarity with the canonical texts it is my belief that the Law of Gravity, for example, is an ongoing miracle, even though my reason and senses have been dulled to its effect and Source.
Thus, as an observer so far, I tend to lower the bar significantly where the supernatural is concerned. So much so, in fact, that a virgin birth, turning water in to wine, walking on water, rising from the dead, healing diseases, etc. is only slightly above the routine where the creation is concerned.
Vied for members, perhaps, but there was no Grab-the-Leader Prize for winning that battle as would have been possible when the Roman emperor got involved. Pardon me if I am skeptical that somehow the "winner" (however defined) did a successful sweep of the world to rub out all the earlier records, sent hither and abroad, that did not *quite* match the "winning" doctrine. The gospel wasn't chained. It would be like trying to stuff toothpaste back into a tube.