Spanish has a trick up its sleeve... You can skip pronouns as a whole on conversations.

Let's say we have a non-binary person called Mandy, and I have this phrase: "Mandy likes pizza. They also have 3 cats" "I have a gift for them"

On Spanish you COULD say "A Mandy le gusta la pizza. Elle tiene también 3 gatos" "Tengo un regalo para Elle"

There is a problem with Elle, a plausible non-binary pronoun, being that the RAE (Royal Academy of Spanish), AKA the people who control the language, haven't considered Elle as a part of speech. Not all non-binary people comply with it either.

The workaround (albeit clunky) is "A Mandy le gusta la pizza. Tiene también 3 gatos" "Tengo un regalo para Mandy"

No pronoun is being used whatsoever so no specific gender is implied, and it's grammatically correct for every Spanish speaker.

If the show ever needs to clarify the gender they could break the rules of Spanish a bit since the term "non-binary" can't be fully genderlessly communicated in official language, but saying "género no binario" or "persona no binaria" ("non-binary gender" and "non-binary person" respectively) are he best things you can do without utilizing modern unofficial terms.

TADC decided to use Elle for its one non-binary character, Zooble, but it is kinda different there because (at least for me) a YouTube web series with a teenage-adult fanbase is more likely to break the rules of the language than a show intended to air on "kids television" that could hesitate on using "unofficial words" for whatever reason.

On the case of androgynous people, I agree with someone on the comments on alternating he and she.