After reading your reaction to Greninja's ban to Ubers I do feel for the struggle you'll have with planning your team for the Kalos third version/sequel since you heavily frown down upon using anything classed as Uber in competitive play.
But you do always like to use the starter most associated with the character so I guess it's probably why you want to play as Serena and use Delphox. I remember you had a problem when it came to OR/AS that you wanted to be May but her associated starter was Blaziken (which is also Uber) but then the animated trailer suddenly had her with Mudkip's line as well so at least that settled on you using Swampert.
I don't usually play like that when it comes to my in-game runs. I just like using my faves.