Question about ASUS ROG Crosshair VI Hero

The mainboard is overkill!
The Corsair fan will not work because the case has the SP installed and the LL are other models that are controlled differently and require a different controller.
The monitor only has 75Hz, better buy one with 144Hz: ASUS VG248QE (24", 1920x1080)
The keyboard only glows blue, if RGB is important to you I would advise another keyboard, for example: Cooler Master MasterKeys Pro L RGB (USB, CH, cable, MX-Red)
If you want to drive uniformly take the motherboard: ASUS ROG STRIX X370-F GAMING (AM4, AMD X370, ATX)
If you really want a water cooling system, you can also go for the normal Masterliquid and buy 3 additional SP fans (one for the back, two for the radiator). You can then control all the SP fans synchronously with the controller that comes with the Corsair 570X.
For the graphics card, I would go for this model because of availability (it's also Asus): ASUS GeForce GTX 1080 STRIX A8G-GAMING (8GB, High End)

Regarding the SP fans: Corsair SP120 RGB with controller (120mm, 3x)

A controller is included with the 570X case! But it is cheaper to buy the package of three with a controller than three times a single fan. So you can save money. :)

Take a 1700X otherwise it looks good...