Sure, Pikachu is generally the one in the limelight, but since Pikachu won't be getting a Mega Evolution (probably, I won't rule it out), I would think Raichu would ride Pikachu's coattails and get a Mega. As for Milotic, I thought Wallace would have Mega Milotic in Episode Delta when he uses his Champion team. Since he's obviously good friends with Steven, it would make sense for him to also get Mega Evolution.