I have that RS360 kit, you should receive 3 fans with it. I suspect someone was lazy and copied over the the 240mm kit specs.
The difference between the two kits is mainly the pump, but also that the more expensive one has a better radiator and comes with compression instead of barb fittings.
1. I would say thats worth $100 in components, but dont expect $100 of more performance though. Only if you were including a GPU to the loop the performance difference between kits would be noticeable.
2. Nope, or only marginally so. I think the copper version has a bit less restriction compared to the normal Acetal version, but it doesn't affect performance. Its just an aesthetics thing.
3. Fan shrouds help performance by effectively removing the dead spot behind the fan motor. But again, dont expect a massive performance boost. Its really only for trying to get every last bit of performance possible.