Don't forget that you're a good 18 months away from getting anywhere near a UCAS form - your DD won't be applying until the Autumn term of Y13, and her aspirations and interests may very well change in the meantime. Most people's do - e.g. my fourth AS that I was originally going to drop became my degree subject.
Make sure any degree is BPS accredited - otherwise she will be very restricted in terms of actually working in psychology afterwards.
Ensure she realises that degree level psych is much more sciencey than A Level psych - if she really struggles with / dislikes the maths and biology elements of the A Level, then she should think very carefully about whether or not it's the right course for her.
You'll be narrowing down her choices using her AS grades and A2 predictions, so you won't end up looking in any detail at all those hundreds of courses. If she is predicted CCC nowhere asking for AAA will take her, and if she's predicted AAA, anywhere asking for CCC would be a waste. As RM mentioned, whatuni is useful.
I'm afraid, however, that she will eventually have to go through all the modules of courses she's interested in - it's the only way.
There are also some options to do joint hons psychology and linguistics at uni - Oxford, Bangor, Edinburgh, Lancaster and Sunderland all offer it. Kingston also offers English Language & Communication with Psychology, and Sheffield offers Speech and Language Science (which looks more theoretical than S<)
She should be more than able to find a combination of AS that will fit all three courses - I would be thinking along the lines of English language, psychology, a modern foreign language, biology, psychology and maths (not all of them...)