No surprise, but Aria is the Delphox trainer mentioned here. It also seems they will show another PokeVision video of her during the episode, this time with Delphox.
Well it doesn't say that it's about that episode, but it probably is.
Also, we do know that Aria is here, so she probably is Delphox's trainer.
...I really can't tell. Is that Aria or Jessie dressing up as Aria in the bottom photo?
I dunno, but I'm pretty sure that's Jessie in the top picture. If that is the case, then the woman in the bottom picture has slightly lighter hair colour, so...make of that what you will.