Paul did not know the accounts traditionally attributed to Mark, Matthew, Luke or John. They were all written after his death. Luke was written some 60 to 90 years after Paul had died.
Secondly, Paul explicitly states that he did not receive any of his teachings from any human source. He got them directly from the Lord, presumably in the form of visions. Thus he did not get his ideas of baptism, Last Supper, substitutionary death, resurrection, Coming, and so on from any person. They are his ideas. His opponents were the Jerusalem party led by James, Jesus' biological brother. The Jerusalem party saw Jesus as being nothing more than a human, with human parents. The birth narratives are highly ingenious creations of imaginitive minds; unfortulately, they did not collaborate and their stories seriously contradict one another.
Thirdly, Mark and Luke were Paul's adherents, and thus followed his lead. The NT Canon was set by Paul's followers, not by James' followers (Ebionites).
Doug