Regarding private use of firearms to down drones over private property, it's not always as simple as defending your vertical airspace. In a crowded suburban environment, unless you're shooting straight overhead, then you might be lobbing projectiles into a neighbor's yard.
I remember one New Year's Eve party I held for neighbors in my side yard in Miami FL. At midnight, among the usual fireworks I heard a clatter of what I first thought was rain falling on the nearby palm leaves. I held out my hand, and caught some shotgun pellets. Harmless, but still annoying. There could be other situations where you might take out a neighbor's window or worse, if you shoot at a drone hovering over your yard at a low enough angle.
Maybe the regulations could be flexible enough to allow it in rural areas, but I don't see this being practical in the suburbs. The answer seems to me to be regulating against private use of drones over personal property airspace period, with exceptions for things like roof inspections, real estate photos, etc. when commissioned by the home owner.
What's needed is a way to easily ID each private drone so they can be reported, when busting local laws. During a town parade recently, someone's drone flew briefly over my yard, presumably shooting photos of the parade route a block away. It was annoying. All I have is a photo taken on my phone, showing a tiny drone over my roof, without enough information to ID and report it. There must be some technical answer for this. Maybe each drone required to broadcast a signal that can be picked up on any smartphone as an ID and linked to a photo, so people could document incursions over private property.