Mixing imported and procedual animations

I want to have a rig do some normal animations imported from blender, but also have a few bones that I can move around manually via scrips.

However, the moment I enable an Animator on the model, all the bones get frozen in place. I already tried using a mask on both the animation importer and animator layer, and while that stops those bones from being included in the animation, it still doesn’t allow me to actually move them.

I assume you could probably do this by having the bones in question not be part of the avatar, but there doesn’t seem to be any option to actually do that.

Is there any way I can achieve this?

Just use LateUpdate to run your code after the animation update and before the frame renders.