yurigadaisukida…I ask this not in criticism, but in honest curiosity on rigging (Been using UE4 and Blender for about 2 weeks now, and my rigs are having issues in UE4, but are fine in Blender 
lol) anyrate…you mentioned snapping, Why can’t you just snap the bones from the imported Mannequin in place rather make a new rig ? Also, other thing was, I am gonna try it now but typing to finish post…I saw Blender did not import FBX, is there a trick to this? (Again, gonna try this so atm I am lacking that experience) Other than those questions, I really am glad I found this post, I been wanting to use the UE4’s rig for the animations on my character I made 