“Milayde” would work! Fantastic suggestion.
I’d like being non-binary to be a normal everyday thing. Like, “Oh, look, Paul is a ginger.” Or, “Oh, Suzy’s a soprano.” It’d just be, “Oh, Cyrille does what ze does.” So yes, it’d be a common normal everyday thing. (Also since there are going to be a lot of people-turned-into-objects, it seems especially silly to make gender a particularly divisive force. Who wants to play a game with a sexist or transphobic teapot?)
I am debating making being non-binary particularly canon by having them called the ‘fae-touched,’ implying that non-binary folk are perhaps half-fairies (fairies being non-binary). I’m toying with that though and I don’t know if it’s necessary. Might be too much extra frou frou. Thoughts?
Really, I’d prefer the knight didn’t ask. Ruins immersion, I think. It was just coding-wise the only way I could manage thinking of a (graceful?) way to include an input option. 
So I’m quite grateful for the multitude of other options that have been presented.