I'm not entirely sure about costs, CC but I wouldn't imagine it would be a small undertaking. I think she'd benefit from some form of physio and that's not likely to be cheap. On the plus side, I'm told she has definitely shown signs of improvement and while it's not thought she'll ever "function normally" she does have the potential to improve.
A fosterer isn't really the ideal solution long term as Nicky is utterly over-run at the moment and as you say, she needs to rehome so she can take more on. I think she also feels that Pumpkin should have a chance at as close to a normal life as possible in a forever home.
No, the condition is not CH. They aren't 100% sure what's wrong with Pumpkin.
I'm not sure what things could go wrong with regards to leading up to her needing a vet, but if this home that is a potential works out the lady in question has three other special needs cats and has passed a CP home check, so we'd get a vet reference and take it from there.
Janey, I agree. The number of times this little one has seen a vet I'd hope they'd comment if anything looked awry in that area.