The above image demonstrates same skeleton retargeting. This allows for animation reuse without duplicating the animations which is kinder on your games memory budget.

I’ve rigged the central and right hand rigs with maya to match the UE Quinn model, the models for these rigs themselves were taken from online. The only differences are with the extra joints added to describe appendages such as the skirt. The skirt is not animated in maya as the original animation does not contain this information, the skirt is Unreal Engine Physics added on top of the animation as is the hair.

Joints need to be oriented the same way as the source skeleton to work correctly, otherwise limbs may animate in the wrong axis.

Alternatively you can use IK retargeting to have a much more adaptive means of retargeting, but this requires animations be duplicated and costs more memory. This can be useful in a pinch but I would save it as a last resort for efficiency,