Miller 2019,
Welcome. With pieces of cancer remaining from a prostectomy you are an unusual case from what many posters see. Keep in mind none of us are doctors so our opinions are just opinions.
A second opinion is almost an absolute necessity from what I read. Most practices see prostate issues as a primary concern and bladder cancer are often down the rung. A University setting or teaching hospital is where I'd try to get to. An MD Anderson, C;eve;and Clinic, Stanford, Sloan Kettering as examples.
One word of caution on radiation. It may be a best treatment answer but, ask questions. IF you have to have a cystectomy radiation can destroy some tissues needed for such a surgery, so you want an experienced and knowledgeable team, one that does at least 25-35 of these a year.
Keep posting as others will add insight.