If the fuel is removed before the optimum time for Thorium consumption, there is more U-233 present. It is possible to operate the reactor to optimize U-233 production, which produces a lot more U-233 than otherwise.
Whether you "burn" U-235, U-233 from Thorium-232, or Plutonium-239 from U-238, there are always fission fragments -- highly radioactive light elements produced by the fission process. These are always nasty. I don't know all the details of the Thorium cycle, but anyone who tells you that there is no radioactive waste is lying, just like they are lying about no bombs.
Do a search for Operation Teapot. Mixed-core of plutonium and U-233.
I know I said last question, but I want to be be clear about this.
“highly radioactive light elements”
Half-life for these?
Sorry, I never was a nuclear physicist, been out of school for decades.