Dave,
Welcome to our world although none of us wish you have the need to be here!
While none of us are doctors, and not knowing all the details of your bladder cancer, there are many that have used different chemo agents in place of BCG. I am just not up to all of them as I only had to do BCG. Perhaps others will chime in with what they have used and why.
Assuming you are comfortable with how up to speed your medical team is on new agents, there have to be some options. At the same time, I encourage a second opinion at a leading-edge center or teaching hospital like MD Anderson in Houston, Cleveland Clinic, Northwestern in Chicago, Sloan Kettering etc could have ideas especially with so many other areas of your urinary tract involved.
Keep asking questions and someone may have other information.