It is great, @Festoonlights, you and your DH are being very open to the advice provided on this thread, even if some if it is slightly strident in tone; all of it is well meaning and much of it very, very useful; I have learnt lots!
I think the single most important post has been one by @poetryandwine strongly encouraging your DD to really push that Maths AL into A territory; your DD has her plan in that regard and is on with that anyway, so that is encouraging.
For me, @Letsnotargue's post as a Biology grad working in the sustainability sector is helpful in highlighting there areas of recent (and possibly continuing) job expansion but also areas that are (and may continue to be) less well paid even if rewarding by other metrics; so we need to be wary of sweeping assumptions (eg 'green jobs everywhere'; 'studying economics makes you rich').
'Lets' also highlight that having a rigorous scientific degree (which Biology most certainly is) provides a solid grounding that keeps doors open and can be a launch pad to further specialisation;@thing47 echoes this point. Some bio degrees at some unis can be quite wide ranging (especially north of the border because of the inherent different in approach).
It is not surprising that your DD is drawn to 'combination' degrees (eg joint honours, minors, natural sciences). I have two observation here:
Firstly, demand often outstrips supply in relation to flexible degrees and Natural Science courses at top unis are very competitive; so 'go for it' but perhaps do not pull all eggs in that particular basket.
Secondly, non-traditional degree or module 'labels' can hide a multitude of sins, with some being quite superficial in approach (think 'bandwagon' marketing). Ensuring the degree has a rigorous, analytical core at a uni well regarded for that core subject is one defence against that trap.
In relation to the point above, @sendsummer makes the case very well that your degree (whatever the title and focus) ideally needs to develop quantitative, analytical and communication skills and that degrees with a rigorous scientific core have the added value of 'domain knowledge' that can valuable if you are looking to enter the consultancy sector, for example.
Finally, Land Economy at Cambridge can have quite a legal and policy focus to it and so appeal to some students for that reason, and others less so. My role means I interact with a huge range of professional sectors across most regions of the UK and, as it happens, I recently met a Cambridge Land Economy grad and a Durham Biology grad, both working in well paid and fulfilling roles in the land management and environmental consultancy areas; again proving that it is important not to get too dogmatic about 'the right course/path'.