I am looking at Diancie's Pokedex entry
Maybe the theories that you need a Carbink to transform into a Diancie could be true.A sudden transformation of Carbink, its pink, glimmering body is said to be the loveliest sight in the whole world.
Cold blooded reptiles like those Helioptile are based on fry in the desert sun. Dry Skin isn't that back-asswards of an ability for it. Not that IRL animal kingdom logic should dictate in-game stuff, but I'm just saiyan.
Sand veil certainly is kind'a odd though. It'd make sense if it made its home 'round the Power Plant, but since that ain't the case, ya've a point with that one.