Well Hanako loves her brother and is on his side, refusing to believe he killed her father so obviously she's not going to turn on him without V.
In my theory, Hanako is stronger at origin story, which has been cut.
At the meeting which leading the ending, Hanako told V everyone knows Yorinobu killed his father, but Saburo's death is a truth, that's why she is at the disadvantageous position, and she try to fight.
At festival, Yorinobu try to kill her.
So they should be a typical "Child of King", cruel family.
Someone use BUG to watch the Float which Hanako stand, they find some door.
I think in the origin story, Takemura have a good meeting of Hanako. At least realize that Hanako refuse him because she is in danger.
Then Yorinobu's ninja rush in, force V to save Hanako.
Only idiot will believe that Takemura will kill Hanako. The low-level security of festival is obviously prepared for Yorinobu‘s ninja, V mess it, and the attack push Hanako turned, and find some initiative.