Possibility to quickly switch between IK and FK. Solve Loop in parents problem.

The main idea is to create a very simple but very functional IK-to-FK rig with the use of simply IK Constraint and Child OF Constraint. With just only 1 Armature (not 3), without any drivers, with any custom rig. Fk is animated simply by bone hierarchy. Ik chain is animated with IK Effector with the use of IK Constraint. When it's needed for further editing, it should be possible to copy animation from FK to IK and backwards. It is easy to copy animation from IK to FK - just by baking bones animation and zeroing IK constraint. However, to edit later animation in IK, it is difficult to copy animation from FK limb chain to IK Effector. It can be done using Child of constraint from the last limb in chain. But it becomes impossible, if there is an IK constraint using this IK Effector, created for needs described above. The IK Effector starts to lag behind animation. Even if this IK constraint is zeroed of switched off (eye button). The only way is to DELETE IK constraint, CREATE A NEW Child of constraint. And then it works. Now we are able to bake FK animation to IK effector and edit it using IK. But it is extremely time consuming to delete and create both constraints every time you need to switch between IK and FK. I understand that there arises a problem called Loop in parents, as IK Effector is present in both IK constraint and in Child of constraint. But the thing is that when Child of constraint is needed, IK constraint is switched off, so it does not participate in IK chain completely. Can it be regarded by program as if it were really DELETED and can it be eliminated from calculations of Child of constraint? That would be just great. Very simple and powerful tool for animator, allowing to quickly switch between IK and FK animations on one and the same custom rig, without use of any other rigs, constraints or drivers. See file attached. Example of how it works in other soft - Motionbuilder. It allows to switch between these 2 constraints without deleting one or other.