Here is my theory.
Comey has millions in ill gotten gains from Billary.
So he put people he has the goods on to investigate Billary.
Meanwhile all these other investigations going on.
Without him noticing someone WHO HAS THE GOODS ON COMEY got put in charge of the Wiener investigation.
Oh, crap! He has to go public with it.
It is obvious that this is NOT due to serious evidence, or threats to national security because by just setting up the server to obstruct justice that bar was already met.
Of course we have been hearing about the mutiny in the FBI, so that put more pressue on Comey as well. This is likely worse that we’ve heard. The problem is that Comey cannot fire anyone, as they will go to the press.
This is pretty close to your theory 4 with some different aspects pointed out.
I like it. ANY FBI that was involved in seeing the huma evidence wouldn’t trust Comey and tell him you do it or we do it. i dont know.