You seem to have jumped from "It's not clear what role, if any, gender identity played in this case." to "Gender identity played no role in this case."
Imagine my shock.
It has struck me what things I have NOT seen any coverage in the press. Because both the victim and the attacker are juveniles, it's understandable that details would be sparse, but it's even sparser than I imagined it would be. Until yesterday, I saw nothing to corroborate the father's claim that the assailant was wearing a skirt. In court, though, that was corroborated.
There are two things that I have seen literally no coverage on, and that I think are relevant. First, did the boy routinely wear skirts or other women's clothes? (And, actually, I have a friend who wears skirts once in a while, but they don't look feminine in the least, nor does he. Nor is he "gender fluid", at least in his public life or in any capacity I know him in. He's all man, at least outside the bedroom, and I don't know or care about inside.) Was the boy known as "gender fluid", and, most importantly to this point, was he allowed to use the girls' bathrooms and/or locker room? Did anyone, especially any faculty or staff, know that he was in the girls' bathroom on the day of the attack? Several editorial writers have made much of the fact that the trans-inclusive school board policy could not have had any influence on this incident, because it was only passed a month later, but that misses the point, in a big way. When the policy was passed, did it overturn existing practice, or affirm it? Was this boy allowed to use the girls' bathroom?
The second thing I have seen no coverage on is student attitudes about this case as it relates to transgender access and school policy. Yesterday, students staged walkouts protesting lack of safety, but there has been literally zero coverage that I could find about whether rescinding male access to female spaces was any element of the protest. This case has achieved enough attention, like Congressional hearings, Attorney General attention, being an issue in next week's governor's race, that I would think it would merit a little bit of coverage, but I have seen nothing.
Finally a point that is not all that significant that I am certain I could find if I looked, but I haven't done so, is whether school was actually in session on the day of the assault. I know in my school district, and many others, the entire 2020/2021 school year was online. Classes never resumed in person. It's not critical information, but it might provide context on how a boy and girl might meet for multiple assignations in a girls' bathroom without being very obvious. Was it in the course of a normal school day? Or was it that only a small number of students and staff were present?