I am unfamiliar about what depiction of Khârn you refer to.
Awww....so you didn't read my epic short story? I wrote it just for you!
Or find a rational thought or theory on how it could be as it could be. I think ADB get a lot of shit, but he is very thourough with background research unlike many other authors. Frankly the clone-theory seems to outlandish to me, just like everyone is trying to make crazy ideas about Rey and how she is related to both Luke and Obi-Wan.
Wait...are you suggesting that Abaddon is the son of Luke Skywalker? I like this idea. Make it canon!