You are correct in your assumption. There is a standard animation being played in conjunction with the IKControls. The shown example is using two IKControl Instances to move the left and right legs individually. When an IKControl Instance is used on a limb, it will overwrite the animation depending on how strong the weight of the IKControl is set.
Here’s a thread where I go into much further detail on how IKControls can be used with RayCasts to position limbs on a custom rig I designed:
You would be very surprised how ineffective google was in not showing me those existed. Only found your post mentioning that after following the post the other guy linked above.