I could say nothing about that Nightly build, but aside that is MH-Blender-UE4 near a one click soloution.
It works like a charm.
When you export from MH into Blender with a LowPoly Topo, then you have both skins on one model Low/High Poly.
I export them seperately.
I never exported directly into ue4 but how you get rid of the second skin, if you do?
Edit: If you look at the zombiefamily in my Signature, they where made to learn process of making clothes to use directly into MH. If you make the clothes for the middlesized, then you can use them on every model (with sometimes small errors (easy to fix in blender)).
All works very well, retargeting too.