@Riot, How Should Players Interpret LoL's Original Lore?

Well, they said they were gonna retcon the entire setting (read toss it out and replace it with something entirely different, Trundle style).

Then we didn't hear anything about the new setting for most of a year.

We still haven't.

Anything that's related to the institute of war in any way is 100% not cannon Champions whose lores aren't related to the league will stay almost the same just like But champions like are gonna have completely different stories

If the old lore doesn't contradict the new lore, its cannon... For example, even if the new lore of Cass and Kat do not mention that they are sisters, they are.

I think in general, everything is the same exept for league of legends. Lee sin is still a failed magician, Cho'Gath is still a ravenous monster, etc. Unless it is directly changed, like the bilgewater event champions, we can assume it is the same.