So sorry to hear about your mother's problems. She (and you) have a lot to consider. Perhaps this is the time to get a second opinion at a place that specializes in bladder cancer, or if you already are at one from a second urologist. When I was diagnosed my urologist said that if it ever came to the time that I needed a cystectomy he would INSIST that I get a second opinion. I am thinking of places like MD Anderson, Memorial Sloan Kettering, USC, Stanford, Johns Hopkins......If you let us know your mother's geographic location maybe someone will have a suggestion for you. There may be other options for her.
As for a urinary diversion, the Cleveland Clinic has an excellent brief discussion of the three possibilities
my.clevelandclinic.org/health/treatments/12546-urinary-reconstruction--diversion
Also, a neobladder is sometimes not as successful in a female as it is in a male.
The most important factor in obtaining a successful diversion is the experience of the urological surgeon. You want one who has done many many of these surgeries...not just two or three a year. Don't be afraid to ask questions about this...how many and how successful they have been.
Wishing you and your mom all the best
Sara Anne