I think besides elementary schools, the uniform is just the top piece. At least I never had any pants as uniform after entering middle school.
I do think some scholl prohibit skirts, and all boys and girls must wears shorts/pants, but I don't remember much anymore.
Hairstyles I don't think it ever having problems in my time. I knew people that had like pink and purple hair and going to school normally.
And yeah, bullying sucks and it's a shame many places don't do anything to avoid that. This year a kid was killed after getting spanked by his bully, after MONTHS of informing the administration about the bullying, which said administration just told the boys to resolve it themselves. Like, what???