Hi MandM - don't know how I missed this earlier!
Yes, DS has raised shoes and a night splint. His leg length discrepancy is now 5cm (congenital bone condition - i don't know anyhting about CP), and he has a riase on the sole of his shoe, and a special orthotic insole inside.
I think it sounds really good that your dd is getting orthotics support - both for stability and because if she has a discrepancy, this can cause serious back problems in the long term.
DS wears a splint at night, and used to wear one in the day, too. If she ever does need one in the day, it might be a 'DAFO' - dynamic ankle-foot-othotic' (you may well hear her splint called an AFO). They really do help stability, as well as helping the tendons and soft tissue to stretch into the correct angle.
WE have the same problems with choice of shoes - DS wears Piedro boots and until this month, the orthotics service refused to supply more than one pair. After other problems, I have moved DS to the central service at the hospital and we now have two pairs of shoes. But restriction of choice is an issue, and I don't think there's much of a way round it.
Orthotists usually use nice warm water to do the plaster casting - after all they have to work with their hands in it too - if you get any fuss in future, ask if it is warm water.
DS loves all the fuss and rigmarole with plaster and cutting it etc!
Ask if you can transfer the insoles into different shoes - maybe you could buy two pairs of the same model but in different colours? Or they might make you two pairs - I don't think insoles are expensive for them to make. It's if they supply the specialist orthopeadic footwear (in split sizes!!) that they really start to mutter 'budget' and breathe in through hissed lips!
Put 100% cotton socks on under the splint at night. More comfy, less sweaty.
Good luck - I hope your dd gets on well with it all.