Coster, 46, in only his second competition in the Northern Hemisphere, put in a tremendous effort with his quality on the board, carding just 11 penalty strokes, for the best individual pen points of 0.55, while Smith scored best in the pen judging.
In the open final, Te Kuiti legend Fagan, 51, competing as an independent, won the race to the finish, taking 13.59 and heading Smith by 4s. Smith's superior quality, including again the best pen judging points, was enough to claim the title.
Lone English finalist Berry was third, and Coster was fourth, again averaging less than a penalty per sheep on the board.
A New Zealand selection also won an international relay, while Northland's Brya Harrison was third in the Lakelands junior final.
Smith and Coster, beaten by Scotland in the first match of an eight-test tour, meet England again at the Great Yorkshire Show this week.