From your character blueprint (for eg the thirdpersonchar), you can add skeletal mesh component and then assign a skeletal mesh to that component (can be added or edited in level blueprint for eg too). The added skeletal mesh will keep it original 3D space coord from it blender fbx file.
For editing and saving it 3D space location, i believe you can just called Costume for eg and set a transformation to it, then save it origin, new location etc in an array to finally save in a save file.
