I’ve been thinking about the idea of Neytiri and Spider having familial soul marks on their wrists, appearing without warning in the aftermath of the Sea Dragon incident. But this wouldn’t be a magical fix or a sweeping reconciliation. The bond doesn’t erase everything that’s happened between them, nor does it mean they’ve fully healed from their respective traumas. (Throw in the two of them mourning Neteyam while struggling to accept their soul-marks and you've got angst galore.)
Instead, I imagine it as a slow-burn acceptance—an undeniable connection that forces them to learn to face each other not as estranged acquaintances or strangers, but as individuals bound by circumstance. It's a long road they walk together, and it hurts, but over time, they begin to understand each other (not easily, and not without conflict), but it's a start.