Was the church of the twelve apostles Jewish or Gentile in its orientation?

The church of the twelve apostles was Jewish in its orientation. The Gospel of the Kingdom preached by Jesus in the twelve was still basically Jewish, connected with Temple worship, the Old Testament covenants, and the promise of the coming Messiah. It was not yet the Pauline revelation to the Gentiles.

Les explains that the early church had only the Old Testament Scriptures, since nothing of the New Testament was yet written or circulated. Apollos knew only the baptism of John and the Gospel of the Kingdom preached by Jesus in the twelve, which was still basically Jewish—connected to Temple worship, the Old Testament covenants, and the promise of the coming Messiah. Priscilla and Aquila later expounded to him the way of God more perfectly, bringing him the Pauline revelation that the blood of Christ is the way to God.

Was the ministry of the twelve apostles Jewish or was it part of the new church age?

The ministry of the twelve apostles was Jewish, not part of the new church age. Their Gospel of the Kingdom remained basically Jewish, tied to Temple worship, Old Testament covenants, and the promised Messiah. It required repentance, baptism, and belief that Jesus was the Christ, while the blood of Christ and the Pauline revelations belong to the new church age.