Hi, I am just wondering about re-targeting and different skeletons. I’ve read the documentation and I think I understand but for sake of clarity, I’ll ask the dumb questions 
If I own an asset, say a biped monster and its rigged and animated…can I take the mesh and basically model something similar to the proportions of it, then import it into UE4 and re-target the skeleton from my original asset?
What type of complications can I run into?
Thanks in advance
Humm this does not sound like re-targeting to me?
Re-targeting is used when the naming convention on one set of animations do not match the naming convention of another so the re-targeting of the animations would be “set1 > set2”
Targeting, as in the mesh shares the same rig and animation, then the first rigged character model would be the master and all other imported targeted to use it’s skeleton so would be “mesh1 < mesh2”
As I read it you want to target to an skeletal asset already in UE4 and the asset you wish to import shares the same rig then yes during FBX import you can tell UE4 to import using the rig already supplied.
You can just reskin the new mesh to the old skeleton you used and animated - and get a new character for “free”. Be careful that his proportions stay similar though.