The heavily bearded man in the centre front of both photographs is Sir Henry Brougham Loch, later Lord Loch of Drylaw.
Loch was in southern Africa from 1889-1895, but I would put the photographs circa 1893-1894, when Loch was involved in the affairs of what was then Matabeleland and Mashonaland. Which fits in with Carrington being there.
As to it being one of the Crealock brothers, I think we can discount this.
Henry Hope Crealock died 31st May 1891, which pre-dates the photographs.
John North Crealock was in the U.K. from 1887 until 1892 still serving with the British Army holding staff appointments. In 1893 he was sent to the Madras Presidency in India as a Major-General. He died in Rawalpindi on 26th April 1895.