I have contacted be quiet! customer service about their fans compatibility with the H100i, and they say it can't be plugged into the Commander Core and thus can't be controlled by iCue. They suggest using a splitter to plug the fans into the CPU fan header. I haven't got a response from Noctua, though.
I remember I have a spare fan from Cooler Master Hyper 212 Evo, I've checked that the fan support PWM so I plug it into the Commander Core hub but iCue doesn't detect the fan, even after I restart the app and my PC. When I change the H100i stock fan's speed, the Cooler Master fan seems unresponsive at all. TBH I hesitate to buy fans from other brands and be able to control them via iCue.
Let's say that I buy another Corsair fan, maybe an ML140 to replace the rear casing fan, can I plug it into Commander Core, and will it shows up on iCue? Or do I need to buy the twin pack and use the included Lighting Node Pro hub?