Like someone else said, the joke was that Quina was amorphous and they didn't know whether they were a he or she. It won't fly today, but I hope they don't straight up make Quina non binary, because they weren't. Quina had a gender, we just didn't know what it was.
Ideal scenario for me on how they can handle this in a remake is to drop the joke entirely since it'll just create bad publicity, and Quina has plenty of other comedic relief elements to work with.
They just need a single scene of Zidane or someone asking something along the lines of, "What are you?" And then Quina says something like, "What you mean? Quina is Quina." Or something like that. Keep it vague still, but don't ignore it. Just don't have it be a recurring joke.