White hair and prehensile hair, both at once.

[Jeefo]

I know there's been some discussion on the these two subjects, but I can't seem to find a definitive answer on how they interract with each other. The prehensile hair hex provides an extra limb that uses intelligence instead of strength as its governing ability. The hair can be used as a secondary attack. White hair, from the white haired witch archetype, recieves a primary natural hair attack, that, as written, uses intelligence only for damage. Nothing written about if it is prehensile or what it uses for attack rolls. So by RAW, white hair is not prehensile and uses str for attack rolls.

But if someone with both the hex and class feature decide to activate the hex, then make an attack roll, what do they do then? Do they use int because the hair is now hexed to be a limb which is governed by int? does the hair become prehensile, but still use str for attack? are they still able to make white hair combat maneuvers while using prehensile hair?

[Cruel Kindness]

As best I can tell, RAW would suggest you make your melee weapon attacks per your BAB, then make both attacks from
each hair "source", assuming the white hair is eyebrows and prehensile is from your scalp making them "separate limbs", at your highest BAB -5 from being secondary natural attacks.

The secondary condition (that -5) is from attacking with a melee weapon in the same attack action, as well as the wording on both of the abilities.

Edit: The governing ability in this case only applies to damage rolls per the rules for making natural attacks.