If the keys given to Peter were so important, then why were they only mentioned in 1 out of the 3 tellings of the story?
The point is that the keys were not the point of the story.
The keys do give me pause, but not enough to believe in secret teachings or evolutionary theology.
The fact that they were mentioned once is enough. The keys were an integral part of the story, or do you think Christ uses symbolic language for superfluous reasons? There is no "secret teaching", we're not gnostic, and evolution is not a dogma so no one is required to believe it at all.