imo you're going to need something that can utilise fighting attacks, because in Unova, Plasma has TONS of things that are weak to fighting. Scraggy was amazing to use in-game for that reason, really. And there's also the fact that two of your Pokemon are weak to dark, and they're in the elite four. Since you have nothing really to counter that then there might be some issues for you.
Zebstrika also apparently has a bad reputation in-game, or its previous evo at least. For example, since its base stats indicate its attack is higher than spA, you'd be training it until 47 to get Wild Charge, which is like the only useful thing, really, since most of its other STAB attacks that are physical aren't that high in power, so unless you wanna use it as a status based Pokemon, like, teaching it wild charge as backup, and thunderwave + toxic and something else, then you're not really going to get far from that moveset.
Whereas if you replaced it with Scraggy, it covers your weaknesses for the elite four, aka dark+fighting which is really helpful in Unova. As for Stoutland, yeah I've used better (than Herdier at least, but hey up to you), and its non-STAB moveset as far as TMs and learnset goes isn't really that good, or high in power (physical that is) so you wouldn't really be hitting anything with super effective attacks often. And the only real use otherwise is Surf, which you could otherwise give to Samurott for your HM usage and since it's special, it'd fit fine.
What attacks were you thinking of using on your others?
