If this rumor turns out to be true, then things are going to get outrageous!
Hydrappl: The most bizarre of the rumor. Not only would it be the first Bug/Dragon type, and it evolves from one of Applin's branched evolutions, But also potentially a Triple-typed Pokemon thanks to one of it's potential abilities. And with 600 BST, it would be a unique pseudo-legendary. Overall, the appearance would be based on apple worms, hydras, and the "Poison Apple" from "Snow White and the Seven Dwarfs".
And that is why i think the rumor is fake... since one of Hydrappls abilities makes it permanent Poison apparently, so then whats the point in changing it to Bug/Dragon in the first place.