Pretty sure Kinemon is not a Zoan. His power of 'disguise' is actually pretty useful if you think about what he could presumably do with it. Since the clothing he made is warm, the disguises he makes have the properties of the things he's basing them off of. So he could suddenly, for example, create armor, additional (melee) weaponry, shields/barriers. Plus he's a haki user… There's no need for him to be some sort of Tanuki/Fox-Man.
I don't see Jinbe dying. I don't see him being denied his promise to join Luffy in the future either. I do think that people break down 'power level' way too much, that the series has shown Luffy, Sanji, Zoro and Jinbe to all be in roughly the same league and capable of similar feats.
But we don't need to discuss it, as we have an ultimate 'end goal' of when Jinbe will join (~the defeat of Big Mom) and we even have a point where we can start contemplating it as definitive (Luffy's next bounty raise). So yeah. He hasn't joined yet. He and Luffy just have a standing agreement based on trust and friendship that he will join once he's taken care of his business. One such item of business is, coincidentally, something the Strawhats have already begun to deal with, and depending on who Law is targeting, will be dealing with very shortly.
OH! Oh man... how great would it be if the Strawhats start their assault on Big Mom, with the bomb in the Tamatebakko (I'm sure I misspelled that) going off right before? Or during? Maybe it messes up their carefully laid plan... Or they beat Big Mom, get their treasure back, set off the bomb, it collapses the castle/fort/ship/whatever and they end up with nothing to show for beating a Yonko?
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One more thing, actually. I was re-reading this week's chapter, and thinking about how natural Kinemon looked next to Sanji and Brooke as they were perving out. Then I thought about how he and Brooke fought, with Brooke leveling out against him, and how he uses a different sword style than both Brooke and Zoro... I want to see what happens to his son, but I'm starting to get this feeling about Kinemon... if we REALLY wanted to preserve the overall dynamic of the crew, then we'd need someone from each of the three internal combats levels in the Strawhats to join, right? Luffy said, "At LEAST 10," didn't he?