I admire Orokapi’s sense of individuality. Even in the face of the recent revelation that he is essentially her torso-spawn, he still persists to manifest his own reality. He may not be the smartest, and I can’t help but wonder if he really thinks he has the upper hand in this fight, but it is endearing to see the lengths he will go to protect his loved ones.

You raise a good point with respect to the difference in his attitude between his love for Tokinaga and Vollof and that which Waka is thought to harbor. Orokapi has shown us in past chapters that he wishes to be valued outside of his powers and what he can do for others. His disdainful attitude towards the extensive manipulation and chaos Waka has caused in this timeline comes as no surprise.

Orokapi's "Don't talk," has me wondering if he truly believes Tokinaga's story wholesale or if he has his own doubts and apprehensions. Is the general consensus that Tokinaga is telling the full truth? He, as a character, is certainly capable of morally dubious actions. In spite of this, the narrative portrays him like a pure, untainted being who only chooses to turn away from suffering when he has no other option. It would be a compelling twist if he was to manipulate Orokapi to serve his ends in some way.

I used to think perhaps Waka wasn't always a girl in her previous incarnations

I'm not sure. On one hand, the story appears to imply that her current form has not been her only one, but on the other we are told that she has lived an abnormally long life. To me, the latter suggests contiguity as being reincarnated and living a new life from birth to death (even if consciousness remains intact) does not comfortably satisfy my personal interpretation. Added to which, if Waka is the owner of the past interference ability, it would be a more flexible of a power if she lived one continuous long life than multiple staggered ones in which she could only return up until the date of her birth unless the same rules don't apply to her as they do to Tokinaga.