SOLUTION: This is a Unity 5 issue, they are wrongly assuming that everyone uses pulseaudio. There's a link further down in this thread to the KSP bug tracker, where someone posted a 'pulsenomore' tool as a workaround. This tells Unity to stop looking for pulseaudio, and stops the segfaults on launch. Audio works, the game launches, and everything runs great.
I also ran into the 'empty menus' issue, I've set my resolution to 1363x768 instead of 1366 as another workaround. Other resoluti