Azurill?
And i'm still highly doubtful that they are female forms. While they certainly have design elements which look like they belong on female characters (Thundurus' chest is actually enlarged behind the breastplate as compared to his original design, which doesn't help his case), i think Pokemon wouldn't do that. Without getting too political, there'd be a huge uproar if gender changes happened given these are "beast" forms. Humanoid male pokemon becoming female animals? That sounds like more political scandal than GF would like, and it's not like it's even necessary for the plot or anything. Also, the moustaches generally say otherwise. It's rare to see (from a character design point of view) a female character with a moustache.
Also, Am i the only one who hopes the Champion Tournament will include the E4 as well? It's a shame those characters only get one appearance and then get left out and forgotten. Not that they were too memorable, but some of them were neat designs. It's be nice to finally be able to have them pose a challenge. Like, having to fight through 4 of them where their teams didn't suck.