What a lucky escape. I know it's been traumatic for all of you and distressing for Mollie, but it could have been so much worse and I'm glad things are now looking a lot more positive.
One of my previous Cockers had a serious kidney infection when he was about 10 months old (the fear initially was FN, but it turned out to be an infection of unknown origin) and it did some damage to his kidneys. But I was told by the vet that in young animals the kidneys are pretty good at being able to do a degree of self repair. Hopefully the same applies to Mollie, especially with the support of medication for the next couple of months, which wasn't available 25 years ago when Sam was ill. He recovered fully and went on to live a normal life with no further kidney problems. I hope the same applies to Mollie