>>28022500I would also just like to add that besides Mallow, we've seen other indications of evidence such as Popplio learning Disarming Voice and Sugimori tweeting a picture of Tiger Mask.
Now, I wouldn't say that Disarming Voice absolutely confirms these leaks, or that it confirms that Popplio will even become water/fairy.
But one important thing to consider is that unlike other moves that are learned early on, such as Bite and Rollout (which are learned by many Pokemon who possess the physiology to perform these moves), Disarming Voice is learned through level up by very few Pokemon. It's actually a relatively rare move. Most Pokemon who learn it are fairy type, and those who aren't are cutesy or fairy-like, such as Meowstic, Swablu, and Audino (don't forget that Mega Altaria and Mega Audino become part fairy type as well).
Litten learning Bite doesn't say much. Many Pokemon possess the teeth to bite. It's a common ability to have. But Disarming Voice implies that the user is capable of soothing enemies with their voice, which is not something most Pokemon can do. This move actually fits the siren/mermaid theme very well, since sirens and mermaids are well known for their beautiful singing voices.
As I stated before, this doesn't confirm the leaks to be 100% true, but it definitely lends credence to them.