Of the eight orders, only two are discussed in my Western Sufism: the Sufi Order of Inayat Khan (chapter by Geneviève Mercier-Dalphond) and the Mevlevi Order of America (chapter by Simon Sorgenfrei). The other six are not discussed, as they were established less than fifty years ago.
In terms of new research, the two most valuable chapters are by Bazzano on the Shadhiliyya of the Palestinian shaykh Muhammad Sa‘id al-Jamal (1935-2015), and by Rasul Miller on the Tijaniyya among Black American Muslims in New York City. Nothing significant has been published by anyone on either of these before. The Tijaniyya chapter is especially interesting for what it shows about gender.
Two chapters usefully summarize unpublished PhD dissertations: Sorgenfrei on the the Mevlevi Order of America from his “American Dervish: Making Mevlevism in the United States of America” (University of Gothenburg, 2013) and Melinda Krokus on the Ansari Qadiri Rifa‘i Tariqa from her “The Poetic Body: Love and Knowledge in a Transnational Sufi Order, the Qadiri Rifa'i Tariqa” (Boston University, 2014).