It all breaks done to the "nature of consciousness", which isn't fully understood yet, even we have a lot of insight.

In my view, the "nature of consciousness" lies somewhere in the computing, in the dynamics, in the current and neurotransmitters flowing into the brain (or it's simulation), more than in the actual configuration of neurons. So scenario A and B are unethical, because the process is there, so the consciousness is there, but scenario C to E aren't because there is no one to feel it.

Even without upload, if you using nanotech you synthetize many different set of brains, representing each "step" of a person being tortured, but each brain being frozen in time (kept at extra low temperature, or accelerated near the speed of light, or whatever), there is no one feeling the torture.