Yes, I notice that people are already commonly using "they/them/their" even for singular to create a gender-neutral or gender-unspecified pronoun.
Another problem with "xe" is that the Vancouver area has a large ethnic Chinese population. When Chinese is written in Latin characters, the "sh" sound is written as "x". I know a Chinese woman named Xi, pronounced "she". They will see "xe" and pronounce it as "she" as well.
We don't have the equivalent of the Academie Francaise. Language changes arise organically, they can't be imposed. Instead, the Vancouver school board should tell teachers to stop correcting students for using "they" as singular when the clear intent is to avoid writing he/she, "he or she", or "he" to refer to any person.