Oh! 

Good points. 

Jude was a traitor and should be replaced. So they did. They did not add anyone else to the rank of apostles themselves, though, the one who became Paul was also an apostle because he directly received his mission from Jesus. So, while the original 11 could choose a replacement for the traitor it was and is Jesus who appoints any other apostle to that position. Not another man. 

This is exactly the same as all the OT references that you bring up: God appoints prophets to judge Isreal. It follows that God will appoint prophets to judge/guide/shepherd His church. Again: God does that, not man. Even those that are given the gifts are the spirit are not always appointed as leaders of the body of the church. They may go out and preach the gospel or admonish as congregation, but... Not everyone gifted prophecy after the ascension is supposed to be a church leader, nor does that make them an apostle.