There need not be any 'mis-gendering'. The child's name can just be used instead of any pronouns.
I am wondering whether schools need to just take a very hands off approach to social transition. Of course, if a child is distressed for reasons they say relate to gender identity then they are given the equivalent support for any child that is distressed for other reasons. But after that then schools could try treating it like a vegan child: 'thanks for letting us know, there are menu choices to suit as follows'
So: 'thanks for letting us know, here is the gender neutral toilet and changing facilities they can use if they do not wish to use the one matching their sex'.
Name changes - same policy as for other students wanting to use a nickname or middle name.
Pronouns - n/a (see above)
What else is there for schools to do?
A child saying that they have gender identity needs to matter to a school as much as a child saying they are vegan or are converting to Islam.
Some secondary school teachers teach hundreds of student, I simply don't think it's fair for them to remember different pronouns.