The order on the UCAS form is not preferred order. Once the offer has been made they cannot change their minds and give a different offer. So the idea that she has to guarantee them being her firm choice to get the grade offer is not true.
When she has all her offers, she will be in a better position to decide firm and insurance. She will have a better idea of the grade she is likely to get and have had time to think about where she wants to go.
I would list three of the RG she is keen on and the 2 non RG, and worry about this when she comes to decided between the offers.
The course DD wants to do is only offered at a handful of RG unis, who all want AAB/ABB, and 2 of the former polys who will accept BCC. After speaking to the admissions officer at one of the RGs they would interview her and may make an offer with slightly lower grades, closer to her predicted grades of BBC, but she would have to put them as her first choice.
But, there's always a but, she thinks the other course would fit in better with her future plans, so my questions are
if she puts the better (imo) uni first and gets the grades does she have to accept that place or could she go to her insurance uni? and
is she better putting the other uni as her first choice in case they're oversubscribed with applicants who've listed it as their first choice and there's no place left if she doesn't get the grades for the other one?
BTW Is anyone else open dayed out yet - I want my weekends back!