Brigade matching is still required in order for an enhancement to take effect. Coat of Many Colors would work for one turn, but then would not work in future turns, since coat would be discarded at the end of battle. You would have a Saint of Virtue who would enter battle with Spiritual Warfare attached, but it would do nothing and be discarded because of brigade mismatch.
Now, if you were somehow able to add another color to Saint of Virtue with Training in Righteousness....
