I do see where you're coming from. Allow me to tell you how it runs with me.
Your statement .. suppose for sake of argument that it were possible for someone to be omniscient (i.e. knowing literally everything) ..
seems contradictory. I cannot believe that a person, with a limited brain, intelligence, life span, etc (i.e., finite), can ever literally know everything (i.e., infinite). Can you even imagine someone having infinite knowledge ? He would need an infinite space to put it all in, and probably, an infinite span of time to assimilate it - particularly given that new and further knowledge of infinitely more things and events would be coming up all the time.
Thus, the juxtaposition of 'person' and 'omniscient' in the real world, is to me nonsensical, and if I supposed it, would simultaneously suppose that anything flowing from it would be also.
We cannot take a term such as 'someone', i.e., a human being, and suppose upon him omniscience, because for a start, that is not the ordinary definition of a person. And BTW, I was interested to read on another thread, where a contributor was railing against too narrow a definition of words on these forums, another contributor pointed out that these forums rules require for words to be used only in accordance with their dictionary meaning. And in no dictionary will you find omniscience as a description of a normal person.
Now, I'm NOT trying to pull rules here - I'm sure I sail against the wind myself on the odd occasion. And I do like the odd flight of fancy myself. But it IS a flight of fancy to say 'suppose someone is omniscient'. No logical discourse can follow from that.
I personally believe that these paradoxes (certainly the one in question) arise from different folk attributing different meanings to words - a nuance here, an inflection there, a not so subtle leap of faith elsewhere .. before you know it - confusion and chaos.
But anyway, I do enjoy the interaction and thinking about these things, and by no means am I trying to assert a superiority of view here - I'm just sayin' how I see it.
PS - will read the one on #35 soon.