In 1900, Edward Dafydd Morris (yes, that middle name is spelled correctly) published a commentary on the Westminster Confession and Catechism, entitled Theology of the Westminster Symbols. Like Francis Beattie's commentary, Morris expounds the teaching not only of the Confession of Faith but also the Shorter and Larger Catechism. In addition, however, he incorporates the teaching of the Westminster Form of Government and Directory for Worship, as well as the Sum of Saving Knowledge. That fact alone makes this a fascinating find.
Morris was a professor at Lane Theological Seminary from 1867 until the end of the 19th century. As a student at Auburn Theological Seminary, he was influenced by New School men. I haven't read through his commentary yet, but it will be interesting to see if his take on the Westminster Standards is affected by a New School theology.