I was like...12 years old when I watched the series.
I don't remember a lot about it, but I remember Gren xD
I don't...actually know what non-binary means.
I have an idea of what it means, but I don't know exactly what it means.
But if it's not consistent to the plot, it shouldn't change.
Usually a character's race doesn't pertain to the plot unless it's a story about black slavery or the Yakuza or whatever.
I know people want more equality and role models, but removing one thing to boost another doesn't come off right.
It's like saying "It's not okay to be who you are, but it's okay for others to be who they are!"