The earliest feast days of saints were those of martyrs, venerated as having shown for Christ the greatest form of love in their willingness to die a violent death rather than reject their faith.
The title “confessor” was used for saints who had confessed their faith in Christ by their lives rather than by their deaths. Martyrs are regarded as dying in the service of the Lord, and confessors are people who died natural deaths. A broader range of titles was used later, such as: Virgin, Pastor, Bishop, Monk, Priest, Founder, Abbot, Apostle, Doctor of the Church.
Cardinal Newman was, therefore:
a Confessor: he confessed his faith by his life and died a natural death
a pastor: he was a priest
because of his immense theological contribution, he could, at a later date, be made a Doctor of the Church.