I'm sticking with the computer providing audio cues to improve pilot situational awareness.
Realistically speaking, even in atmospheric combat you don't hear the other guy fire, only yourself.
I always figured the ani as either superheated air from a slow leak, or bits of armor from a hit that liquified some of it.
Oh, and the shockwaves: Yes, you do get those in space. Just not very well. But shockwaves from supernovae have a lot to do with the current theory of star formation. Considering the power of the weapons used in FS that produce shockwaves (The Harbinger would make any current atomic weapon look like a firecracker, and the Tsunami would too. Their successors even more so.), they seem reasonably sized and do reasonable amounts of damage.