Welcome,
Many of us will question your report where you say 3 "flat" tumors found. If these are CIS, which is a flat red/lesion like, these are ALWAYS considered high grade and definitely a concern. I would get a copy of the path report and ask your URO if they are seeing CIS? IF, you have any questions get a second opinion. Often those simply confirm the previous DX.
Passing blood clots 10-17 days past is common due to the surgical site shedding things. If the blood is dark or old, it is probably not for concern. It happened to me and if I was alerted to that I would have freaked out. Red, or fresh blood would be a concern after 3-4 weeks. The chemo wash could also cause the irritation via blood passing. Either way, you need answers.
You really need to ask your URO more questions as none of us are doctors and get real answers. We are volunteers that have been there and done it. If you go for a second opinion, get a teaching hospital or university setting that really specializes in bladder cancer. MD Anderson, Northwestern or U of Chicago, John Hopkins, Sloan Kettering, Moffit in Tampa has a good reputation, Emory, USC just to name a few from past posters and compilations via rating services.