So I was messing around with the Capeman mesh for 3R and had an idea. I replaced his usual keyframes with Grenadier's male_cape_eternals... let's see if he notices.
Lo and behold!
He moves with the keyframes but the mesh is rotated 90 degrees forward into the hroizontal plane.
If I understood Nifskope better I'd see if I could fix that.
You should be able to edit the scene root to rotate it back to the correct location. i'll have a go and see if it works at all.