The order of which the constraints are created does not matter, but the order of which they are calculated does. You can drag the constraint order in Setup mode. Constraint order is done from top to bottom.
I've created a simplified setup for you.
aim-simplified.spine
Under Constraints
there are three constraints.
first the aim
constraint which is a single bone IK constraint that yields the aiming direction.
then the torso
constraint which is a transform constraint that constrains the rotation of the torso
bone to the aim
bone at 50%.
and last the head
constraint which is also a transform constraint that constrains the rotation of the head
bone to the aim
bone at 50%.
If I were to change the order of those constraints to:
1 torso
.
2 head
.
3 aim
.
the torso
and head
constraints would be calculated BEFORE the aim
constraint, and would result in the bones not rotating at all when moving the IK constraint target aim-target
.
I hope this clarifies. But like I said, it would be much easier to help you if I had any idea of how your constraints were set up. A screenshot of your Constraints
nodes would probably suffice.