Do you think that the yin yang symbolism concerning Kaneki and Touka will come into play or does it only concern the original manga?
I think the yin/yang is supposed to represent their shifting but opposite positions on the Ghoul/Human spectrum.
The Yin is nurturing and passive in nature, like the peacefulness and reticence of the Human World, whereas the Yang is strong and active in the same way that the Ghoul World values violence and independence. The Yin is black where the Yang is white - Kaneki’s transition between the two is made pretty clear with his changing hair colour, and more subtly Touka shifts from Yang to Yin. But the merging of Kuroneki and Shironeki into Haise at the end of the original manga and Touka’s reconciliation of the two halves of her own personality unite the Yin and Yang within themselves, and give them the balance they need - although Kaneki still struggles to accept this balance for a long time.
So one is no longer firmly Yin and the other no longer firmly Yang. They are now both complete and standing side by side, and can finally, truly communicate.