Quite right about the Boer artillery - more speaking in terms of numbers and weight. The British could rely upon more consistent artillery support through the heavy naval detachments and horse artillery, though the Boer Nordenfeldts were very effective from defensive positions. I am interested to hear that the British put captured models into service - not that surprising I suppose given that a British equivalent was adopted in short order.
It makes sense that the Boers, as an irregular army put together for the war at hand, did not have common equipment. I thought that the point was worth making that the majority of Boer riflemen were likely armed with the 1888 Mauser (alongside many others like those you name) - as opposed to the 1898 which was unlikely to have gotten through in anything other than small numbers, so the war was not fought with ''Mauser actions'' in the sense many people today will think of them.
I would think it pretty unlikely many 98's made it through to the Boers, given their isolated and landlocked country. Perfectly possible some arrived from German South West Africa and some beforehand along with the other materiel the Afrikaaners received, though. Be interesting to know how if many actually saw action.