She would look sooooooooo Cute as a Mermaid
also, she would be a fantastic Pokemon Performer because she in total sync with her pokemon, especially Popplio
Her starter in Kalos would probably be Froakie, because for a water type trainer
Her Kalos Pokemon Team would be:

Brionne
Moves: Bubble Beam, Icy Wind, Aqua Jet, Disarming Voice
Z Move Hydro Vortex

Frogadier
Moves: Aerial Ace, Water Pulse, Smokescreen, Quick Attack

Clauncher
Moves: Bubble Beam, Water Gun, Swords Dance, Ice Beam