I do not presume for an instant that this Poke will be using its Poison STAB on any kind of common set, not in this metagame. That said, by bringing weather into the conversation this early on, we're committing to a making Fire-type that doesn't just check bulky waters but also functions well independently in Rain (Electric immunity next?); while an interesting idea, it still makes the CAP flounder offensively in lieu of good non-STABs like BoltBeam and such. I favor Dry Skin as the primary Abilility only because it gives CAP a chance to heal off SR with good prediction AND do some good Rain stalling when there's the chance. That's a good, albeit bizarre niche for this Fire type, since via typing this CAP is already fairly redundant on a Sun team in terms of stacking weaknesses, especially to SR. Now CAP can handle Rotom-W and VoltTurn to an acceptable degree as well, killing two birds with one stone (Rain and VoltTurn).
Water Absorb is of course a close second for me. Stealth Rock has pushed so many Fire types out of OU they had to get Drought in order to be let back in. Giving CAP the opportunity to come into battle at full health in specific situations (besides Spinning) is a step in the right direction for the concept at this stage of development. I'd like to focus more on the speedy Ground types and Terrakion moving forward, which I think should check CAP and vice versa, so I hope in stats we can figure out some good numbers for this guy.
"You may say I'm a dreamer, but I'm not." - John Lennon