1. it's not unusual for floating rotors to have some 'play' in them. that is how they 'grow' when hot without getting warped etc and they find their own kind of path through the caliper. i'm not certain from that vid if there is anything wrong or not. but have a good look at all the rotor buttons that attach the outer rotor to the inner piece and make sure they are all there and not damaged/missing. check the mount bolts too.
2. no. that site glass if used to find Top Dead Centre (TDC) when rotating the engine by hand. it has the various timing/firing marks in there and you should line them up with the little arrow at the bottom.
3. it's the clutch slave cylinder. when you squeeze the clutch lever it pushes the piston in the master cylinder (on the bars), that compresses fluid in the brake lines and that fluid then pushes on the clutch slave cylinders piston which then actuates the clutch (releasing the clutch so you can shift gears)
4. no idea on the code but it's more likely a 'trim' code or some other code relating to the frame or to the spec of the bike.
5. it's a very old interceptor type ECU (from the look of it) that uses trim pots to adjust ign and fuel up or down from factory settings at various points in the rev range. very basic and pretty old looking but if it's running nicely I'd be tempted to just leave it alone.