a slight head nod to their friendship still being cannon.
It's never been canon.
The "Friends and Rivals" thing was just website dressing, as far as we know. There were a lot of inexplicable examples of champions that would never know one another, but were "friends" or "rivals" because there was a thematic link. Ahri and Wukong is a great example, in the old lore they're on other sides of the world, but they're both animal people, so "Friends".
That said, I wouldn't be surprised if Riot made it canon at this point. So many people think it is, and honestly that fan comic probably got read more than the original lores for the characters, because it was such a huge success.
That said, Riot has expressed trepidation about taking ideas from fan work in the past, so that may be a dealbreaker. Still, we've seen community skins (Surprise Party Fiddles comes to mind) and in-jokes make it into the game before, so it's certainly possible. While I personally am not a fan of either character, I wouldn't have a problem with the additional development that could add!