Pip's quite right! henchmen don't get most of the good lines, like sidekicks do.plus they aren't named, personalitied, or carried when they're sleepy. they get left behind and cut loose or turn on the mastermind, not adopted and loyal enough to go to jail. and they tend to come in groups.plus, pretty much by definition, sidekicks are cute and henchmen aren't. and if there's anything Pip is, it's cute.
There's the standard "cute minor villain" character, but Kitteh is cute too. Cats have no morals, so we can forgive Kitteh's life of crime; they're sort of like Raffles, and he definitely had a sidekick, not a henchman.