In this tutorial, walk through retargeting motion capture data from Vicon to a MetaHuman in Unreal Engine. Create IK rigs and a retargeter in order to use mocap data with a MetaHuman. Explore the new MetaHuman Creator UI in 5.6. Block a scene with mocap data and the Unreal VCam app which can be used for pre-vis and pre-production.
https://dev.epicgames.com/community/learning/tutorials/WvLR/unreal-engine-vicon-motion-capture-to-metahuman
Thank you, this is very helpful.
I have also used the auto-create retarget chains to speed up the process and edit them.
Did you find a way to retarget fingers?
It seems pretty complex to manually align fingers 
You can set up chains for fingers (thumb, index, middle, ring, pinky). It might require additional cleanup, but it is possible. In the Vicon capture, you could do a 2 or 3-finger solve with interpolation so that it’s not as intense.
Auto-create retarget chains is super helpful! Thank you for the comment!