(Blender) Bone not animated from an advanced character rig

Hello,
I have created a rig based off of the p2design effective rigging tutorials. In a chapter about rigging the weapon, the weapon is snapped to either the left or right hand with a property driving the influence of a Copy Transform bone constraint. I used this technique and two constraints to snap a pistol to either the holster or to the hand.
When I exported the animation, the pistol bone stayed in the holster position, even though I keyed the property that drives the influence on the constraint.

  • I am using blender 2.82a and Unity 2019.3.9f1

  • I am using fake user for the action, no active action on the rig

  • I exported the FBX from blender (FBX Units Scale, Deform Bones Only, No Leaf Bones, Bake Animation)

  • After importing, I created a humanoid avatar and configured it

  • I am also exporting animations as separate FBX files for organizational reasons

This is first time I’ve tried a complex blender rig in Unity, so if anyone with experience integrating Blender in their Unity Game Dev pipeline can help, I would be grateful.

Okay, so I’ve come up with a theory as to why the weapons are not animating. It’s that the weapon bones are not children of the hand bones, and also are not part of the humanoid avatar.
6127451--667925--WeaponBones.jpg
I made the weapon bones children of the Root because they have a holstered and drawn state, and an animated property in Blender determines which. If I want animations on these bones, what do I need to do?