While I don't think the Kalos Trainer is very likely the more I think about the idea of using her the more I like it. People look at this thinking it needs to be the three starters but in Truth it doesn't need to be. Lets pretend Kalos Trainer would replace the original Kanto Trainer. It's possible for them both to exist but I doubt they would more or less make three whole new Pokemon characters to add to the thing even more so if they then added another new Pokemon or something .
She could have Charizard, Greninja, and Sylveon. This line up has the Pokemon that matters most from first gen (at lest excluding Charizard ), an Eevee evolution with expands through the generations displaying the newest type in the process, and Greninja who is by far the most popular final evolution of the new starters, it has by far more usage competitively at the never lest, making it the proper choice of the three. This could really be a perfect line up of three Pokemon and each gives different kinds of Pokemon fans excitement.
While Pokemon X and Y doesn't really have an exciting new face for Pokemon like some previous gens do this generation still did something amazing, got fans of old Pokemon and new Pokemon together to enjoy a cool new game and later wait a long as time for Pokebank. I do think X and Y deserves to be represented to at lest some degree and this could be the perfect way. Id miss the Kanto Trainer but I think this could be even better. I don't want to go into move sets or anything but if you have any ideas you want to share with me please go ahead.