#3
Yeah, what he said. When you pick right at the bridge it's easy to hear how twangy of a sound you get. Conversely, when you pick directly on the neck you can hear how warm it is. Even if you aren't picking in either position, it's still how the pickups tend to hear them. The pickups are angled because the higher strings sound a little too sharp and piercing otherwise.
#4
because the closer to the bridge the sound becomes more trembly and less bassy so the angle is so the higher strings dont sound to trembly