It's not an Avatar reference, because according to Pokemon X and Y, before entering Shalour City (Korrina's gym) the player goes through a section called "Reflection Cave", a cavern which has (you guessed it) mirrors in the walls. The writers would pull this off regardless of any references.I've been thinking about that situation, and it's made me think. What if M Ash does have a crush on M Serena, and he tells Ash about it, which makes him start to think. The episode, even though him and Serena are separated, could still have large hints. Imagine if at the end of the episode, M Ash realises he doesn't actually like M Serena anymore, but real Ash has thought about it and now looks at Serena differently? It shows the mirror effects and has character development. Wish this would happen.
And loving the references to ATLA, greatest cartoon ever.
Anyways, the mirror episode, I wouldn't really expect anything tbh.
"But JJ! You're so pessimistic about the ship now anyways!" In this case, Pessimism is good. It avoids you from getting hurt or disappointed when something actually doesn't happen. It's a 50-50 chance, the chances between optimism and pessimism are equal.
But here, we haven't had a solid hint since what, ten episodes now? I'm really doubting the reliability of these writers with this subplot.