Alolan Form Gible Line

I thought it would be cool if Gible and it's evolutions got an aquatic theme IF they were to receive an Alolan form. And Gible would be the perfect White Shark poke for a tropical beach theme. Only, I couldn't be bothered to draw up Garchomp, and M-Garchomp. My biggest question is if Pokemon with existing Megas will receive Alolan forms, cos won't they have two different megas then? (e.g. rumoured Fighting-type Alakazam). Anyway, if anyone with more time and more creativity would like to take this idea further, please be my guest. 

Also, they'd be typed as Dragon/Water and have Swift Swim as their ability.