Dwayne Johnson admitted a while back that the character was partially inspired by his grandfather, High Chief Peter Maivia.
Dwayne Johnson is part-Samoan and his father and grandfather were also both wrestlers, which ties them even closer to the culture and mythology of Moana.
We’ll just have to wait for Dwayne Johnson’s daughter to actually believe all of that.
The inspiration behind the character Maui also goes deeper than just The Rock playing him.