Your policy starts in a very non-scientific way when it uses the phrase, "sex assigned at birth." Sex is not assigned at birth but simply recognized and recorded. There are only two genders. To say that isn't so is meaningless, especially when no transgender advocate can specify exactly how many genders there are. If gender is a continuum, then male and female are meaningless distinctions and all the talk about sexism, discrimination against women etc is also bunk.
By adoption these policies, you will reap irreparable harm on the very people you purport to help. The students with gender disphoria need counseling, not affirmation of their incorrect self-view. If you indeed believe that gender is self-determined, then why is your race also not similarly fluid and self-determined?