Arkham Knight - UPK Playable_Mesh_Skins

[BatmanRevival]

This tutorial (https://www.pcgamingwiki.com/wiki/UPK_Explorer#How_to_convert_any_UPK_into_a_playable_skin) suggests any UPK can become its own playable skin but I just keep getting confused around "Step 4" and I don't know what to do. I was hoping to convert either Nyssa or the Rebel assassins into a Playable skin.

 

Another thing, how do you replace capes? I've seen on here that there mods for "Flashpoint cape fix" or "Batman Beyond with a proper cape" where it isn't a Mesh Swap but a whole new suit slot. The mod author even sometimes puts down that such a mod is 'easy' and takes about '15 minutes' to do. How do I do that?