The agreement ended two decades of costly effort by Maori to prevent Mr Kelly building above the Te Ana o Taite burial cave, effectively protecting the wahi tapu site from future development.
The pact set up regular meetings. It covered employment of about 40 local people at the resort and runanga involvement in any changes affecting the environment.
Resource consents obtained during Mr Kelly's ownership, including plans for the construction of about 800 single-storey guest dwellings in pockets near the resort, will proceed, although Ms Herbert-Graves said light pollution would need to be managed so the peninsula would continue to be a prime spot for stargazing.
She said Ngati Kahu had been vilified at past public meetings for raising issues that delayed Mr Kelly's development plans.
Some people now anticipated the worst from the Chinese purchase of the resort, but Ms Herbert-Graves said Ngati Kahu had found Shanghai CRED behaved honourably and kept their promises.
"This is not to say we are pro-development. We favour leasing rather than sale of land to foreign investors, but we are not into denying the rights of people based on their race," she said.
The flight to Shanghai took nearly 12 hours.
But the tough arrival settled into a routine where the visitors started each day's activities with visits to impressive gardens before exploring the city of 36 million people.
"I relaxed. I never had to explain or defend myself as I often have to do in New Zealand," Ms Herbert-Graves said. "Our hosts were lovely humble people wanting to be hospitable." They had "exquisite manners".
The Ngati Kahu group was shown poorer areas where people were being rehoused in high-rise apartments. Streets were cleaner than in New Zealand as "everything is recycled", but water was dirtier and smog created air-pollution problems.
She had learned to use chopsticks to deal with eight-course dinners each containing four dozen different dishes that were laid out for the visitors. "The only things I didn't like were the chicken feet and ducks' tongues," she said.