For anyone seeing this in the future, the setup works.

- No pull up resitor needed, i.e. the Fibaro configuration is "no pull up"
- Used rj12 cable (6 wires) and the relevant pins are pins 2 and 5. Pin 3 was also needed for GND. The mapping is

- Port 1. Pin 3 goes to Fibaro GND. Pin 2 goes to Fibaro Input 1. Pin 5 goes to Fibaro input 2
- Port 2: Pin 2 goes to Fibaro Input 3. Pin 5 goes to Fibaro input 4

I'm actually not using the W channel since my led strip is RGB and not RGBW.

Hope it helps anyone in the future!