The Incarnation is God becoming Man. The Second Person of the Trinity was "there from the beginning", eternally begotten. The Incarnation happened when Christ assumed human nature through Mary. Of this even He spoke whe He said "As my father sent me".
not to the exclusion of other Christians
The scriptural method of "sending" is sacramental imposition of hands (Acts 6); we also expect unity of doctrine ("is Christ divided?"), and on that basis exclude those who are separated from the Church either sacramentally or doctrinally.
For purposes of "sending", is there scriptural evidence that Jesus laid hands upon the Apostles? Acts 6 says that men were going to be sent, and that they were prayed over and hands were laid upon them. I didn't see how the laying of hands was THE signature of the sending. God does all the sending Himself. He sent all believers in the Great Commission without the physical laying of hands.