Most people I've seen using it as their personal pronoun would probably laugh if they were presented with an option for It with Cousin Itt representing it.
I would probably add an option for "thing" with a disembodied hand as well.
I'm way out of my element here, being a straight cis male, so I wanted to mention the setup, but knew I needed to tread carefully 🤣 Thing is great, I didn't even think of that