Welcome Rome91,
All questions are welcome and there are many here that have "been there and done that". Keep asking away as someone will have some of that to add.
While your diagnosis is serious keep in mind this still beatable and treatable disease. Stage 3 means you want to attacking expeditiously, especially with lymph node involvement. The chemo certainly makes sense, radiation not quite as much. With stage 3, I am assuming all have talked about your need for a cystectomy. Radiation can sometimes damage tissues needed for reconstruction on a urinary diversion. Thus, a second opinion is sometimes good for fresh eyes, peace of mind and maybe new ideas. However, you do want to get going on this.
I am attaching a link....just copy and paste into your browser on the pros and cons of the 3diversions. On that subject. When you settle on a surgeon make sure you pick one that does many a year (25-35+ a year).
Some will also have a preferred because that is all they know....so research and questions are vital. Most people that have gone through this are happy with their choices. See:
my.clevelandclinic.org/health/treatments/12546-urinary-reconstruction--diversion