I can see why the DH issue is particularly thorny, especially in education - which is KS's experience/professional background whereas KJK is coming from a parent's point of view.
Schools are coercive environments that generally limit student's choices and freedoms in favour of good order for all.
How far should they go to balance respect for DH, respect for student's differing opinions and good order in general.
How far should DH be seen as 'female' - in all things? Are there limits? Are these self imposed limits or should the school decide?
Would this include entering female bedrooms during a school trip? Chaperoning female individuals when unwell/taking for medical help?
Does DH use female staff facilities? If so, is this to the detriment of staff who have reasons to prefer single sex?
How should DH be referred to in school? Who makes this choice - individuals, the school, DH?
If you leave it to the students then this will cause conflict so I can understand the school taking a fixed position but this is coercive (as are many things in school).
In the end DH has had DBS and checks to ensure suitability for teaching and I don't think ability to teach is being questioned.
I think I would come down to what is best for good order and limiting conflict in the school, which would probably be accepting female pronouns, even if I would find that difficult personally if I were a colleague or parent.
There are always going to be divisions/sub divisions in a large group - especially when there isn't really a leadership structure to 'pull together' towards a common goal - it risks splintering which weakens us all