IK would not help under these circumstances.  IK specifically "locks" hands and feets in place, and allows other children body parts to move and respond naturally to that situation.  A good example is applying IK to hands on a model hanging from a wall or branch.  In your particular case, you want one model to respond another models movement.  Parenting would serve you better.  But, however, applying IK to feet would anchor one model while it responds to the movement of another in a parenting situation.  I have no experience in animation, someone else better qualified may have a better solution.