One thing I wonder about is if the survival of the Natalia Republic would preclude the other states through butterflies.
Also why did the Orange Free State remain separate from Transvaal OTL?
Natalia's likely toast though. The UK pretty much refused to believe they were independent, and really didn't want the Boers to have a port. Natalia was also very poorly run apparently.
As for why the two were seperate, well it's partially due to geography, and mostly due to the Boers being a fractious lot. This had a bad habit of making them not really work together. The one time they ever united, they split not long after.
As for the Griquas, they had issues in competing against the Boers and the UK. They also apparently had a habit of selling land and being somewhat nomadic too, which doesn't help with state building.