1: Yes. Even with a slick fairing, if you can slot in behind someone, you can still get a noticeable rest without losing time on your lap.
3: Yep. These races are aimed more towards school teams, and the Open Category came in later, so we (the Open Category) are sharing the track with riders aged down to senior Primary School, As a result there is an enormous speed difference. Ideally, the slow vehicles are supposed to ride to the left of the track, but it doesn't always work so smoothly.
4: Lights range from halogens through to HIDs (AyUps & the like) and are powered by batteries to suit.
5: Accidents can be spectacular, as you would have seen through this thread, but injuries are, thankfully, quite rare. The worst I have seen was a couple of years ago. A spectator decided to cross the track just past a corner, where he couldn't see what was coming. Not surprisingy, he got hit. Leg broken in three places, rider shaken but unhurt.
Just ride the bloody thing and enjoy yourself!