i'm just gonna sum up everything here with
"raikaria didn't read the journal of justice so just ignore everything he says about the lore"
Yep, totally, let's go with that, despite me saying multiple things which are JoJ related, such as Lissandra being Ashe's ally as far as everyone knows.
And JoJ doesn't cover that much. Especially with more recent champions. Most of the JoJ is honestly about the buildup to the Crystal Scar. For example, Zilean helped in some baloon race for Piltover. That doesn't make him from Piltover. [And Janna helped too but she's not from Piltover!]
Renekton still never reached Shinuma to my knowledge. Skarner was never from there. The closest Rammus was from there was Blitzcrank's matching service pairing him up with a Cactus.
EDIT: Aw forgot to copy-paste this into the edit tab. My bad.