Right off the bat, looking at your team, I definitely think a Gliscor with Poison Heal. In particular, a build similar to the one this guy has in his video:
For those who can't view, the build is:
Gliscor @ Toxic Orb
Nature: Careful
EVs: Depends
Substitute
Protect/Fire Fang/Roost/Taunt
Toxic
Earthquake
Status and OHKO moves are some of the biggest killers in the tree and I notice that team doesn't have a full proof answer to that (Scizor and Toxapex will be immune to Poison and Toxapex can Scald thaw through Freeze but that's it). Hence where Poison Heal Gliscor can come in. Poison Heal kills two birds with 1 stone by giving you protection from status and a form of passive healing that doesn't rely on an item. Protect guarentees you get the Poison off and Sub gives you a fail safe against jank like OHKO moves and stat reduction and is complimented by Poison Heal. Earthquake is a strong STAB to keep you from being complacent and works with Toxic by hitting almost everything immune to it. The last slot is tricky. Protect guarantees you get your Poison. But Roost provides longevity, Fire Fang can get Skarmory and fly/levitators immune to Poison, and Taunt can help you cripple the slow support mons.