All of this is reasonable except this
I can not ever imagine the US Armed services Officer Core ever challenging the legitimacy of the US President as Commander In Chief.
Other than the President surrendering US Sovereignty to a foreign power it is inconceivable.
It is not impossible. There are enough officers that believe in the Constitution and the rule of law. All it takes is one with guts enough to do something. As soon as Obama is delared a usurper or suspected of being one then the US military is bound to move on it. The officers that are “political” and won’t have the guts to move on it will also not have the guts to oppose those who do. It may be surprising to see those that stand up and those that go to ground.
It is what happens after that, that will be interesting