So the "Edison" is not just a coincidence... I still don't understand why he's cat-size.
Probably because he, himself, either is magical-realistic himself or has become imbued with magical-realistic traits by osmosis.
Meaning, he's going to be at the height that Ray and Benniebenniebenben perceive an equal to be.
I mean, he's probably the dead inventor that used to make these items and... the devices created a new him to replace him upon his death but this new him is incomplete/magical due to his simulated nature or... there's no inventor at all but the magical realism of the self-created factory has created the inventor that Ray and Ben would think to be behind such an endeavour.
I'm just saying, a psychic projection of what two very rich cats think an insane inventor would be like... or... the magical recreation of what a collection of inventions remember of their inventor... either way, it would probably scale itself to whatever sentient beings were around to interact with.
It's like Frank Zappa said, imaginary guitar notes and imaginary vocals exist only in the imagination of the imaginer.
That or I've just read too many Philip K Dick novels.