After looking through the code I can say contrary to what is claimed it is possible to get a complete for Hinata, the problem is in the young Hinata part of the game. If you don't go back to the present and talk with her normal self before successfully using the namigan on her younger self then it locks you out of the complete. If you think you've done everything with all three versions check these 3 variables - hinatamission, hinatapick, and hinataslave. If they're be 12, 4, and 12 respectively it means you got shafted by the young Hinata problem but there is an easy fix at this point; just type hinatamission = 13 into the console and hit enter then go talk to "evil" hinata and she'll explain how you created her using the namigan on her younger self.
On the off chance the dev reads this fix the damn namigan option for young hinata so it doesn't lock you out.