I’m not a member of the team 😉
If you want to create an entire new skin, you may want to have a look at the developper program up there ^ (https://overheadgames.com/epic-character-generator/developer-program/).
Otherwise, Pro Pack and postwork is an easier way out in my opinion. Let me show you.
Say you want to add a skeleton to some randomly generated character…
This is just for show but you should get the idea…
Give me a minute.