Cation about EEE, it has a wax that can fill scratches in the CA and when the wax is removed the scratch is revealed. Clean with denatured alcohol after EEE to see what the surface will look like after all the wax wears off. I used EEE a few times, but after doing this test I stopped because there were a lot of scratches that were being hidden by the wax.
Sand through spots won't necessarily go all the way around the blank, depends on the precision of the setup and turning technique. A shiny CA surface can be as little as 0.0005 thick or less, I suspect that most hobbyist wood lathes and turners aren't at this level of accuracy. I have seen many sand-thru spots very similar to the one at the start of this thread. Incidentally, I have never seen a spot like that resulting from what I determined to be oil on the blank. In my experience CA (at least the CA that I use) doesn't seem to be very sensitive to oil.