1) Each wave is marshalled in a pen, there will be loads of folk there to help, you will no doubt be asked to help someone yourself.
2) The bike tends to be a bit strung out but as the roads are closed you should have plenty of room to pass/be passed.
3) No idea, I've always driven.
4) OW experience would be good but if you are worried hang back and stick tight to the buoys all the way round. Its not choppy. they will bring you out to the start 5 mins before the hooter goes, so be prepared to tread water for that length of time.
5) As you exit the water youu will be given a bin bag and you have to get out of your suit and bag it before the will let you into T1. the floor is VERY slippy so watch you footing, especially if you are going to have cleats on. I never use a box, I just have a towel down with my shoes talced.
6) I dont remember the racking being numbered, but its HUGE so try and remember where you have put your stuff!
7) On the bike leg remember the roads are closed so you dont have to follow the white lines (e.g. round roundabouts!) I always see loads of folk add a good distance to their bike leg by religiously staying in lane! And enjoy, its one of the best events I've done, nothing like cycling full pelt into those tunnels!