Wouldn't be surprised if the stock wheels were north of 2kg. Almost anything would be an upgrade. I think 1500g is a good target for a new wheelset, so the wheels you mentioned aren't far off. The rotors will either be 6 bolt or centerlock but even if the two wheels have different rotor interfaces you can just get new rotors to match the wheel. As far as the cassette, 8-11sp Shimano all have the same interface; you may need to add a spacer or two to use the 8sp cassette with an 11sp freehub. Your tires and tubes should be just a straight swap.