In the future it will be, but at the moment it is not. The reasoning behind this is because if we let players drag sub actors around, they would need to have animations like how Byte does, of which we do not at the moment have the production capacity to make those sets of animations. But it is planned for in the future when we are reaching a full release.
At the moment they AI does attempt and does it's best to avoid overlap but it's not perfect.
The Menu displaying which sub-actor is being dismissed has been suggested before! It's on my To-Do for next Major Update!