additionally I bet the ash na'vi agree to help capture Jake in return for guns so they can burn down other tree of souls and na'vi tribes. This is where the forest scenes where Lo'ak shoots a gun and there's fire arrows come from.
Final act is a second battle of the tree of souls which is why there are purple rays in the scenes where the fight on floating mountains since it's the area right above it. That fight on the mountains is preceded by this >>212843873 which would be the omaticaya rushing to defend their tree.

It's going to be pure kino