Think I've decided on my online team. Greninja, Venusaur, Haxorus, Aegislash, Klefki, and Volcarona/Talonflame.
Greninja is my special sweeper. Protean allows me to swap around types and, with Assault Vest, become deceptively hard to kill while I STAB OHKO/2HKO Pokemon left and right. Venusaur is a staller, who honestly I only keep because he also has reliable poison damage, which is necessary with all the fairies around. Otherwise, his reliable CC and healing lets him absorb damage while still remaining a threat. Haxorus is my physical sweeper. One Dragon Dance gives him unstoppable damage. Taunt + Earthquake makes him effective against the very common Klefkis and other debuff/buff spammers. He goes well alongside my CCers and my other big threats - my chances of winning increase exponentially if he lives past two turns. Aegislash is... Aegislash. And Klefki is Klefki.
Deciding between Volcarona and Talonflame. Volcarona has the benefit of defenses, better offensive typing, and countering the very common Malamar. Talonflame has more reliable damage due to his speed, better defensive typing, and is very effective as a U-Turn lead.