My little girl has suffered with thrush since she was tiny - sympathies to you and her. It's a pain in the ** for both. I give her home made pro and pre biotic yoghurt - are you breast feeding? Would that pass to her if you ate it? I dont know, just an idea. And I believe you can use it as a cream too. Maybe best to check with HV though.
On the nappy rash front, my baby boy has been a real sufferer, in disposables and cotton cloth, but we had a break through with bamboo. What type of nappy is she in? Maybe try a bamboo booster as her her nappy to see if helps?
Andwhen the natural type barriers weren't helping I found Bepanthem and Metanium (from Boots sp?) helped heal nasty rashes.