Kia Ora Angela,
Hopefully this helps, Grandad Toki was actually adopted by Timi and Heni Materoa, whwhile they did whangai a no of children, they adopted 2 - Toki and Whare Keiha.
Tuahae was killed in Gallipoli in Dec 1915, I believe Mere had Toki, when Heni found out that Tuahae had been killed she went to I believe Tikitiki to get him from Mere.
Mauhana Turoa and Tiopira Pohatu were the blood parents of Tuahae. Heni and Mauhana were (like us) 1st cousins.
I have some of grandads papers also whakapapa that he had worked on