Why do you need to extend the poison sensitivity? You already have Skullcrusher. If you're placing the poison sensitivity on turn one of each rotation, that gives you six poisons each rotation, which is more than enough. Bulwark's chance to extend the debuffs is likely to end up causing you to lose your ATK down or DEF down instead, because of too many poisons.
More importantly, why do you have Scyl on that team? She's 100% worthless for CB. Drop her for sure. I would probably not drop her for Bulwark either, though.
Right now your biggest problem is that you have no Leech on the team. Do you have someone with that? That would be a huge addition. Given you have Scyl, you're probably not far off from Ghrush. If you already have him - great, he'd absolutely be worth adding in.
The other major thing you're missing is DEF up. If you can drop Scyl for Ghrush, and drop Kael for someone with DEF up, you'd have a very solid CB team.