This thread was a big help, so I thought I’d add my info in case it helps anyone else. Finally completed my retrofit. Main issue I ran into is a lack of coding info, and the fact that some airbags have 2 ground points and some have 3. This is for a 3 point airbag.
CH module
1k8959442 buttons
5G0880201AC Airbag
7E0971584C Harness
Pin5 in the black connector was unnecessary, so I removed it. The blue/white ground goes at the 6 o’clock position. I can confirm the wiring suggestions are correct. I had no backlighting initially. SI’s instructions on page 4 gave me left side lighting. Embryo’s instructions on page 9 provided the right side. To clarify, I could not solder to the gold point as it looks like embryo did, I soldered directly to that transistor leg in front of it. All buttons functional, button backlighting is constant on with ignition. Coded to 0020532 with VCDS.
Many thanks to Bauhax, never would’ve finished this project without their help.