So, my Battle Maison team consists of Sharpedo, Swalot, and Mega Pinsir. I decided to try this on Wifi, not sure how well it would do, but I've actually lost very few battles so far, if any. Granted, about ~50% of the players were pretty noobish, but I'm doing well against the seemingly competitive people so far. Sashpedo seems absolutely fantastic in 3 vs 3, the only things that can OHKO it are priority users and Pokemon with multi hit attacks. And even if an opponent that Sharpy can't OHKO has priority, I can usually just switch to Swalot to take it. Since entry hazards are so uncommon in 3 vs 3, I can generally have Sharpedo take out a Pokemon later with Destiny Bond. Swalot itself is obviously not the best option, but even so it's not useless. It's not easy to set up on thanks to Yawn, and it can get some extra damage in with Infestation and Toxic. It may not have reliable recovery, but Black Sludge manages to restore a fair amount of HP during sleep and Protect turns. My particular Mega Pinsir was not bred with Quick Attack, I think because at the time of breeding it I did not realize that it only needs two attacking moves outside of Quick Attack, namely Return and Earthquake. Regardless, although not as useful as Quick Attack, Substitute is still helpful, mostly to protect against status. I also feel like Substitute > Quick Attack in the Battle Maison, simply because there's so much you can set one up on, but that's irrelevant to battling human players.