now we have this video
[video=youtube_share;e54Tj96BseA]https://youtu.be/e54Tj96BseA[/video]
That is episode 7.
so unless the events in episode 7, happened after William shot his daughter, then it's impossible William was a host.
But it would make no sense that the events were not chronological, because it is William's daughter that takes him to the rescue team shortly after after he is found by akecheta. This was needed for the chain of events to unfold, that lead to William shooting Elsie, in which we are told by the producer the ""Real William" kills his daughter.
Now, the only question that remains is, where is future Host hybrid William (seen in the credits) been placed in his timeline. it is possible that he is reliving this scene, over and over, as a host, but there can be no argument, (unless the show producer is lying), that the first incarceration of those chain of events was carried out by a very human William.
It was all very clearly foreshadowed in the scene with Delores and Logan.
Also foreshadowed by Akecheta, who, after finding William, tells him that Death is a passage from this brutal world, you don't deserve the exit. had william been a host, this passage would make zero sense, as death is NOT an exit for a host.
End of story