When North Island Maori: Ngati Tama and Ngati Mutunga ‘invaded” the Chatham Islands in 1835, Pitt Island was also taken. Those Moriori that were living there were either killed, eaten or taken as slaves. Maori took ownership of Pitt Island when they “walked the land” back in 1835. The Chief that then owned the island named Rangiauria was Mateoro(?)
The names of those Maori families that actually settled on the island ‘back in the day’ are unknown to me at present.
There are a couple of headstones at Waipawa that may shed light on this.