Brembo never makes the rings available separately for sale, it's very frustrating. For some of the Brembo 2-piece rotors (obviously not the CTR yet), aftermarket companies will manufacture rings which re-use the original Brembo hats, but if you buy from Brembo, you have to buy the entire assembly (hat and ring).Most 2 piece floating rotor manufacturers market the rings themselves. It is possible that Honda doesn't want untrained people trying to reconnect used rotor hats with new rotor rings and therefore are not interested in selling rings only. To be fair, if you were paying full labour rates to switch rings, it might be cheaper just to buy the hat/ring combo.
OTOH, we won't know if it is a true floating rotor until someone takes the hat and ring apart. Certainly it looks like the hat is much beefier that the Girodisc ones which may add to the OEM weight.
Agree that noise issues are usually due to inadequate/poorly functioning anti rattle springs in the hardware and with a good manufacturer, OEM or aftermarket, this should not be a problem.
The new rotors are fully floating with spring clips. I don't know if I can link the photos I have as they are posted on a private FB group, but it is a fully floating design. Weight is allegedly the same (24.5lbs), which is odd to me.