Jim,
A complex list of queries. I'll try to respond after a fashion.
A group of Mamluk "refugees" fled to the Dongola region of N. Sudan in 1812 and influenced the area until 1820 when the Egyptian drove them out. One source says only 300 remained and fled to the South. The refugees were soldiers and I doubt they instituted metal working traditions. It seems that only superficial accounts of the Mamluk-in-Sudan and what happened to them after Dongola exist, no scholarly works I am aware of. Seems a fertile area for some serious research.
Dongola and areas south down to Khartoum was inhabited by three Christian kingdoms from after Meroe until the advent of the Funj. They likely inherited and preserved Meroitic metal working traditions. The last kingdom was the Alodia with capital at Soba near today's Khartoun. It fell to the Funj c.1504. Remnants moved south to near the Sudan-Ethiopia border and founded the Fazaghali Kingdom. They lasted until taken over by the Funj in about 1685. A the bottom of the attached Wiki file is a 1821 pic of a Fazaghali man with a sword scabbard with a bulbus tip and a cross guard like the kaskara. This suggests that the kaskara originated in the East rather than the West/Darfur area.
https://en.wikipedia.org/wiki/Kingdom_of_Fazughli
Apparently, the native sword making era was late in coming to Sudan. Traveller's narratives from as early of c.1700 states that the Funj used Schiavonesca broadswords favored by Hungarian & Venice during the 15-16 C. perhaps made in Serbia. Interesting trade connections. Others report large number of European blades imported from Cairo. See pp. 17-20 in my paper on Kaskara Cross Guards attached. Osman Digna supposedly told the Hadendawa of Kassala area to make swords for the Mahdiya.
http://www.vikingsword.com/ethsword/...ara_guards.pdf
Yes, Gordon had a first class machine shop in Khartoum that was moved to Omdurman. The Khalifa had Greek and other artisans keep the river steamers running and even tried to reload rifle ammo. No doubt that spear heads and knives were made there as well. Maybe some sword smiths were recruited as well, but since spears and javelins were the main weapons, most elite warriors likely already had a sword from the zillions of imported blades already in-country. Also, the village blacksmith made tool & simple weapons, but likely didn't have the necessary skills to make a proper forged and heat treated sword.
Thuluth decorated swords were made in Omdurman. While the thuluth etching was on some proper imported blades as is yours, most blades look to me to be from sheet steel with imported cast brass cross guards. For the most part they were for religious purposes not a fighting weapon.
I think I've read that after the Battle of Omdurman the Brits buried piles of Mahdist weapons outside of town. Would be great to find and excavate the spots.
Some times I feel like we are like blind men attempting to describe an elephant as we try to understand the Kaskara and swords in Sudanic history.
Best regards,
Ed