OP
I suggest that you might need to grow a harder skin as I can not see it getting better really.
Kids with additional needs are often picked out and picked on, usually by parents and sometime not without good reason.
My son is gorgeous, funny and intelligent but he's also high functioning autistic with challenging behaviour.
Not invited to a party? Christ he joined a school and 2 parents took their children out of school based on having met him in previous setting and a couple of incidents. The mum ring leading that one is a pure through and through bitch... not only did she engage another parent to remove their child but she solicited support in the playground to the point where the other mums ended up giving me a chance because she annoyed them so much... but I digress because the reason she is a bitch is because I had the displease of meeting her about a year later... I passed the time of day with her as her son and mine were chatting and she pointed out to me that she had removed her son because of 'him' (pointing at my son) in full view of my then 7year old.
Now... a few years on, greyer and wiser....
Your school is probably not being honest with you about the incidents... you see when they have a child with challenging behaviour they have to do handling plans, risk assessments, pay for ed psychs, do IEP, offer behaviour management...
And they probably can't be arsed and if you are taking the flax from the other parents then so much the better.
If she is adopted then you are in luck - there is a HUGE amount of money being ploughed into supporting these children and schools can access it. Do a bit of research on the county council website under adopted children & LAC (looked after child). If no luck then I would defo try to get a CAMHS referral from the GP... you should be accepted no nonsense because your DD is adopted.
Get the support even if you are managing because if school arent then it will eventually spill into home plus you can 'help' the school by 'offering' for them to access the support you have obtained.
As for the parents... well i became friends with the ladies in my son's school... How? I was always upfront about my son's issues and how I dealt with them. I agreed with them that it was totally unacceptable that their children had to put up with my son's behaviour, that the class were suffering because of attention detracted from their kids to my son and I implored them to complain to the school that my son needed to be better supported to benefit everyone. I also explained a little about his diagnosis and how some really simple strategies could help IF they were applied.
The parents supported us 100%....
The school didnt... but that is another story.
You have a long road ahead OP... attachment disorders are 'tricky' and need professional support. I admire your love and determination for your daughter and believe her to be a lucky young lady with you as her mummy x