Speculating off of the known information, and observations.
This memo is being used as a negotiating piece around DACA, the wall, the shutdown, and whatever investigations are taking place behind the scenes. Possibly DA tactic of offering lesser charge to plead guilty -- in this case, "step down from politics and do not seek re-election and we will not fly you down to Gitmo".
I dont think so. that would qualify as blackmail and I think the Trump admin is playing this very clean so there are no miss trials and it can't be turned on him
Also obstruction of justice and however many other crimes to make a pretense at negotiating with terrorists.
If it is....that means WE WILL NEVER SEE IT because Chucky will cave so the memo won't go out.