I'll deal with a few points in no particular order...
With the fact that her school is in special measures, you should make sure that
- this is mentioned in the reference
- you check each uni's contextual data policy (that's the technical term). In some cases she may be given a lower offer, or they may look twice at her application.
However, it's not a free ticket to a place - if I'm honest, she's still at a disadvantage compared to someone with slightly higher grades at a much better uni.
You don't need chemistry to do a physical geography course. Some unis (including RG unis) don't even require A Level geography.
For employment stats, have a look at the www.unistats.ac.uk website, which will allow you to compare various quantitative data sets, including career prospects (the data for the career prospects is drawn from the DLHE survey, in case you're interested). As others have said, going to a non RG does not make you unemployable. It would make life much harder if she wanted to go into a few careers, like law, but there's no sign of her wanting to do that anyway.
Have a look at the WhatUni website, as that will allow her to search for courses by A Level grade requirements.
Geography is a subject that is studied at school, and it's one of the more popular courses because it's an obvious choice that everyone has heard of. If she went for one of the less obvious but related courses (environmental management, disaster management, environmental science, geology, development studies, sustainability etc etc) then she'll often find that entry requirements are lower than for a geography course at the same uni, even when there's a lot of overlap between modules. Similarly, if a course is brand new at a given uni that year then applications tend to be a bit lower and so they can be a bit more lenient with grades (but there's no easy way to search for such courses!).
She could also have a look for geography with a foundation year, which would be a year longer than usual, but a few unis offer it (thought
STEM foundation years are more common tbh) and it might be a way for her to get into a uni that wouldn't otherwise have been available to her.