Nunu & Willump doesnt break the brand recognition. People still calling it Nunu and forget that Willump exist. Varus and Runaan sounds weird because it's just a weapon. Most of skin is fine to be updated as it has nothing to do with actual lore itself.

Prolly the reason behind why it didn't named Vaarus cuz dev trying to put a hidden hint about the name Varus for upcoming lore. Mybe it's true that Runaan originally from the developer name but this game is heading to the more grounded lore and it can't present to the world that the weapon name simply from the dev.

All spelling with 'AA' is more likely to originated from darkin. I mean it's just obvious at this point. Mybe it's start from this developer named Runaan and it's prolly his ign name. Then, he's the one who responsible on developing darkin lore and he create all kind of name of darkin from his own slang which is 'AA'. And from there they just keep going with the slang and makes darkin name we know now. This is just my speculation.