If you want RGB fans, I'd happily recommend NZXT Aer RGB fans. They are good looking and are efficient with airflow. I also went with a Kraken X62 for CPU cooling and since I bought a pack of 3 140mm Aer RGB fans, I had one left (bought 1x120mm for the back of the case) so I attached the remaining 140mm to the radiator as push (only one but plan to buy a second one) and the two air pressure fans that come with the Kraken were installed as pull.
They are not AURA compatible and require NZXT Cam software but since I needed the software to control the Kraken's lightning, I went with them. I highly recommend these fans. Since I wanted to control the RGB fans with software, I also bought NZXT HUE+ that came with LED strips.
All in all, I control the lightning of the fans and led strips with CAM and it also monitors temperatures, fan speeds, Kraken temp, rpm, etc. I only installed Asus AURA to control the RGB in the mobo and the RAM sticks (Corsair Vengeance RGB).
Whatever you decide to buy, I don't think you need any fan splitters. That motherboard has plenty of connectors, it has the same number than the Z370-E which is the one I have.
