KotR should be universal. The dimensions of Super Nova, classic Bahamut Fury and Odin mirror our universe, and there's no reason to think that KotR's dimension is any different. There's one problem with Bahamut Sin scaling to Cloud: Cloud with geostigma > Reno and Rude > the Player Turk >= Jade Weapon >= Zirconiade > KotR Bahamut Sin surely isn't even comparable to Zirconiade. Speaking of which, if there's one summon capable of putting up a decent fight against a multiversal opponent, that's Zirconiade. Since summoning it requires five materias (1x summon + 4x support) one could make an argument that Zirconiade = 5x KotR.
