Move hands from two seperate rig from a single controller I'd like to know if it's possible to move a pair of hands from two seperate characters without workings on their individual animation.

 

The best case would be an empty that moves the hands by adding animation on top of the two characters without replacing it. I hope I am clear enough in my explanation.

Thank you for your time!
Yes, you can.

The two arms should have an IK Chain, you can set a copy location constraint to both the IK targets (Man and child), to follow the empty. You can animate the "influence" parameter of the copy location constraint, so - in the section of the animation in which you want the arms to be controlled by the empty - delete all animation data ot the arms, set two keyframes to get full constraint influence (1.0), and animate the empty as desired (and the pole bones, if present, to set the elbows angles).