I don't expect everyone to share my views, but I will defend them. And I am not saying that Fuuma/Subaru is there in canon - I'm pointing out the elements in canon that show an interesting relationship with them, platonic or otherwise. Obviously the only canon will ever be Seishirou/Subaru and Fuuma/Kamui(/Kotori). You seem to be saying only canon pairings are IC, which I don't think is true. It's perfectly possible to write Fuuma and Subaru together without marginalising Kamui and Seishirou, and the same goes for any noncanon pairing.