I have already stated my concerns with Taunt, especially since we have leverage against literally every one of our checks except Skarmory, Klefki, and Hippowdon. Taunt invalidates Skarmory and Klefki as checks when paired with Head Smash, and I have already stated that this is not going to be used against them in a negative fashion using linear strategies. Considering that both of these mons would easily be able to stop our CAP otherwise, and we want our CAP to be in general threatened by Steel-types, giving it access to Taunt should not be something we should consider. Just for reference:
I would support Encore, but I forgot to mention that I edited it out of my proposed moveset because I could not find any particularly good reasoning for it. It looked good on paper, but I could not find anything beyond just general annoyance that would make it gain any support.
Knock Off is always a move that looks good on paper this generation, but I really do not see a reason for running it. Our CAP would very much appreciate being able to run Dual STABs, U-turn, and either an additional coverage move or a move that gives it significant leverage against particular opponents. Knock Off really does not let it achieve such against opponents it is not going to already beat anyways (except for Garchomp and Ferrothorn, but there are far more efficient ways of dealing with them). Something like Reflect or Toxic Spikes at least puts pressure on a number of our CAP's checks without utterly dismantling them, but Knock Off is more just annoying than being enough for our CAP to use as leverage against its checks.
Thunder Wave tends to be the only thing Klefki needs in order to put significant pressure on the CAP. You can roll out all of these calcs, but they do not represent a real one-on-one scenario in which moves are made in a fashion similar to a chess game, where every move you make counts. You can say these calcs negate my points of concern, but you are assuming these mons will switch in safely, which is not from where I am arguing. Head Smash + Taunt is intended for Skarmory switching in, but everything else I was saying about it reflects multiple different yet common scenarios in which these points of concern would come up. Rolling out calcs and expecting the problem to be solved is not solving any problem, only coming up with an excuse to not solve the problem (no inflammatory overtone intended). Yes, Skarmory can carry Iron Head, but physically defensive sets usually want Counter a lot more because it allows Skarmory to beat a much larger array of targets it is supposed to beat instead of just a small handful of targets.
Knock Off is always a move that looks good on paper this generation, but I really do not see a reason for running it. Our CAP would very much appreciate being able to run Dual STABs, U-turn, and either an additional coverage move or a move that gives it significant leverage against particular opponents. Knock Off really does not let it achieve such against opponents it is not going to already beat anyways (except for Garchomp and Ferrothorn, but there are far more efficient ways of dealing with them). Something like Reflect or Toxic Spikes at least puts pressure on a number of our CAP's checks without utterly dismantling them, but Knock Off is more just annoying than being enough for our CAP to use as leverage against its checks.