An invasion is an invasion.
Really. So you think there is no difference between a foreign army invading and occupying territory and then kicking in the doors of the citizenry, and an existing government doing the same? You don't think they would pose different logistical challenges, maybe?
Analogies are always fraught with peril, and the further apart the two situations, the more perilous the analogy. Here are the four different situations you compare:
How can you think that all of these situations would have the same outcome? How can you even compare #4 to the rest? Here are some of the more glaring differences:
I hate to say this, but you verge on paranoia. American gun owners will never be "disappeared" in the middle of the night. I don't believe this because I trust the government, but because I trust Americans and I especially trust American gun owners.