I realise it's a bit late, but on the young girl self harming, your best bet is to ensure that she always feels she has you to turn to, and that you are there for her. Going behind her back could do more harm then good, but try and make her parents see sense and get her out of that school. I'm 17 and have struggled quite badly in the past year or so, and the days that are worst are definatly the days when you feel alone and as though no one is there for you.
I'm incredibly quiet about the struggle I go through almost everyday, due to the way people react to when you tell them you feel depressed at my age. As though it has to be attention seeking, and that I couldn't possibly have any reason to be depressed, as these are supposed to be the best days of my life. It's horrible, and that is what I got from the people who are supposed to know me best and love me the most. My dad genuienly told me to stop being silly and to man the fuck up.
It all got to much for me and I tried taking my life on the 15th of August last year. My mum found and stopped me, and it's starting to turn around slowly, although I still have days like today where I get really low, and I the fact I haven't been going to the councilling sessions doesn't help either but I hate talking through my problems as it feels as though I'm just asking for sympathy, and that is the last thing I want. Anyway, I know I've gone on about my problems for a bit, which I apologise for, but just be there for her, it's what she will need the most. I hope I've helped offer an insight into how she might feel, as it has taken a great deal for me to post that, other than my mum, GP and counsellor, nobody knows about me trying to take my life.