Very fun scenario!!!
I loaded up the game, and discovered that I could only play at Chieftain level.

So I changed that in the editor to Any. So now I was able to play an Emperor level game.
I dont know anything about this war, but according to your description the English and Boers are at war with the Zulu. If thats the case, then you should make locked war.
The game also crashed for me, when I tried to look at something in the Civilopedia. So I restarted and avoided looking at anything in there.
I first declared war on the Zulu and then allied with the Boer. DAMN, there are a lot of Zulus!!!
Early on the Zulus razed the city of Lydenburg and I thought the whole orange blob in the north was going to get conquered. But for some reason, the Zulus never attacked anymore of my cities. Instead they just pillaged and pillaged and pillaged, and attacking the Boers whom they did eventually wipe out. I was completely surrounded in the north, but the Zulus never went in for the kill, they just destroyed every improvement.
In the end though, I was able to advance from the south and blast the Zulus to hell with my Cannons.
Also, why not make every turn 1 week long??? Maybe even add a time limit, if you want.