Kubur,
I'm always eager to learn. Would appreciate good references. Here's a more recent paper by a Sudanese scholar on the Sammaniya order, the one the Mahdi was first associated with and which revived after Omdurman.
https://archive.org/stream/TheSamman...niyya_djvu.txt
Islam has always been worn loosely among Sudan's regular folk; i.e. Popular Islam. Likely there is a "class" component between Orthodox and Popular expressions of Sufism.
Dissertation's file is too large to attach. I'll try to send it via a PM.
Best regards,
Ed