I'll take you last question because it answers the others. No, it could not happen now. An 1866 Supreme Court case, Ex Parte Milligan (71 US 2 (4 Wall.)) ruled that military tribunals, like the one Burnside established, cannot try citizens in areas where the civilian courts are in operation.
A general orders a law into existence, and a law which is actually contrary to you know, actual constitutional law and this is fine and dandy?
You don't like the dictatorship label, but these are exactly the sort of things a dictator does.
I don't know how the Southron version is supposed to make this sound worse, because what i've heard so far sounds pretty bad on it's own.
This is some Woodrow Wilson sh*t, 54 years before Wilson did it.