A masked guy breaks down your door w/o an Article III warrant absent exigent circumstances? Yeah, I’d agree. Trick will be that pressing the murder charge would be federal since a federal agent dies in the line of official work (though illegal), which would give the president grounds to push for death.
Yes and no. I think you vastly underestimate the military’s stockpile. So, they could subsist for a good while until all the Democrats/“Domestic Terrorists”/Undesirables are dead. Then, they’d just restart. Still though. If the rural farmers from Afghanistan/Iraq can defeat the US military through persistence with sticks, then the same can be done here. Their tactics might even serve as a roadmap.