So to answer your question, no it is not possible for anything to affect us any faster than the universal speed limit of causality (that light happens to be able to hit).
See e.g.: https://en.wikipedia.org/wiki/SN_1987A
Not just that, but lights when it passes through a medium slows down depending on it's refractive index (speed of light in water is about 225 000km/h while in vacuum it's 300 000km/h). This is important distinction as recently we had an uproar when it looked like neutrinos are slightly faster than c (in the end, it was a measurement error).
You can observe effects of particles going faster than speed of light in a medium if you look at photographs of Cherenkov radiation.
How does a particle or its environment measure the particle's traversal of a truly empty space?
300 000 km per second
"Its exact value is 299,792,458 metres per second (approximately 300,000 km/s"
I read that as: Can something come along and snuff us out after we've observed the light wave component of the event, such as a shock wave of some sort?
That is the only way it can happen.
Probably. Why would points becoming more distant due to expansion of space be a counterexample to the speed of light being a limit on the speed of causal propagation? Spatial expansion doesn't move anything, so it can't propagate information.
Not that it matters, because the speed of light is still the limit: if they could influence us when they were closer, that would have happened by now.
It certainly moves matter-energy in different regions of space with respect to one another.
I know that's a weird explanation, so consider:
t0: S~~~>O U (shadow exists)
t1: S~~~~~~> U (shadow exists)
t2: S~~~~~~~~~>U (shadow !exist)
At time "t0", "U" thinks he's in the shadow.
At time "t1", "U" thinks he's in the shadow.
At time "t0", "U" thinks he isn't in the shadow, since the photons are now hitting him.
A similar calculation/thought-experiment can be done for shadows with "angular momentum", in case you think the tangential velocity of the shadow will exceed the speed of light.
t0: SO U1 (U1 in shadow)
t1: S~~~~~~~~~~>U1 (shadow leaves top first)
I didn't do the precise math, but I'm pretty sure the tangential velocity of the shadow along the dotted line won't be greater than the speed of light. The curvature of the "wave front" formed by the tips of the arrows ">" above will be lesser than the dotted line curvature, so the photons near the top of the diagram hit the dotted edge before the ones towards the bottom. This is because the source, S, takes time to move away from O.
Note that the wavefront formed by the photons moves radially outward from S, but ascii art is limiting.
There are similar things that appear to exceed the speed of light:
See "group" and "phase" velocities for similar things to the lighthouse.
Quantum entanglement works faster than light but cannot carry any information. As such the speed of causality (and implicitly of light) is still the real limit.