May I ask why, exactly, you want to declaw him? You know the possible results and all the complications, and what exactly is going to happen to him, so why do you want to put him through that?
Not all cats are the same, so the new kitten may not be so gentle, especially because he is a kitten and doesn't really know better when it comes to biting. When cats are declawed, their claws can't be used as defense, so they use their teeth. Cat bites are more likely get infected than scratches, and they hurt more. My first cat was declawed, and I have plenty of scars to show how he used his teeth, since he didn't have his claws. My last cat, we didn't declaw. I clipped his claws, and he never once made me bleed when he scratched me, his sister, or my dog. Cats and dogs have very tough skin, and they can't easily be hurt by cat claws if they're playing. If the kitten means to harm them, he will, but it won't be bad enough to actually hurt them. Just enough to make them back off, if he's scared. I really doubt a little kitten can beat up a dog or another older cat badly enough to have to be declawed. There are plenty of alternatives, like the soft paws claw tips, and simply trimming their claws.
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