Your list looks correct to me (FWIW).I don't blame you for not wanting to install iCue. I am guessing you have already been down that path.
Thinking this through, if I have this right, you will have 5 x Splitty4's but only 4 RGBpx ports on the Farbwerk360. You could connect the RGBpx of the 5th Splitty4 to an RGBpx port on the Octo, but Octo RGBpx ports are more limited than the RGBpx ports on the Farkwerk360. The other option is to do what I did and get a 2nd Farbwerk360, then connect the RGBpx port on the 5th Splitty4 to an RGBpx port on the 2nd Farbwerk360. Note that the Farbwerk360s operate asynchronously, which could be an issue depending on what RGB effects you will be using. Also note that the
Farbwerk360 comes with 2 x RGBpx cables
#53287 (50cm) and 2 x 15-LED RGBpx LED strips. The Splitty4 comes with 1 x 50cm RGBpx cable and 1 x 70cm 4-pin PWM fan cable, so you are covered for PWM fan and RGBpx cables.
Other stuff to consider ordering:
If you end up adding a 2nd Farbwerk360, you need another USB port to plug it into. All of their USB cables are 5-pin at the USB header end so you can get 2 of them on 1 USB10-pin port. I would just add a
Hubby7.
You might want to throw in a couple of Aquacompter
#53282 adapters. These little guys come in handy if you want to connect an RGB device that has the standard ARGB connectors on it to an Aquacomputer RGBpx port. I used one to connect the LEDs in my Fractal Celsius+ RGB pump to a Farbwerk360 port. They also have the opposite adapter
#53285 that allows an RGBpx device to be connected to a standard ARGB +5VDC mobo port (or whatever).
If you have need of these adapters, you will also need RGBpx cables to connect to these adapters. These are actually just Molex Picoblade connectors, so you can buy the parts to make them yourself if so inclined. Molex also has pre-made cables but I think the standard pinout is different than the Aquacomputer pinout. Easier to just buy the Aquacomputer RGBpx cables unless you will be using a lot of them. Unlike Corsair, Aquacomputer provides these adapters to allow interconnecting their RGB devices to other products. Maybe if Corsair had more confidence in their iCue platform, they would not make it all a closed proprietary system with no provision to connect a non-Corsair RGB device.