In-game scoring

A few questions on how in-game scoring works:

If I laser-designate ground targets for CAS, who gets the kill credit? I assume it’s the pilot who makes the kill.

If an AT infantryman makes a hit on one of the hard armor vehicles and doesn’t take it out, and I come in and make a second hit that kills it, who gets credit? I assume it’s the last player to make the hit and take out the target.

When some player makes the final necessary move that triggers the win in any AO or side mission, does anyone get credit?

On the scoring table, what does the prefix (-) mean in front of the digits? And what does the Greek-looking symbol at the top of the far right column represent?