You can, but it will be better to plug the fan cables into the H115I as it has smart functions so it will automatically adjust the fan speeds based on coolant and CPU temperatures. If you plug them into your commander PRO, you have to set it up manually, which I would not do, as you risk that you mess up and the fans will not spin fast enough to cool the system, resulting in unwanted overheating.
You can still see, and control everything via iCUE, it will just be a seperate tab called "h115i".
Regarding the RGB cables - you should only put those on the same hub as the rest of your case fans if they are the same fan. In your case, the H115I uses ML RGB fans, and your case has LL fans, so they should not be put on the same controller, as they will not work properly (the fans has different numbers of LED's)
But again, you will still be able to control the RGB effects on all fans via iCUE - you just need to do it trough different tabs, so no biggie :)