Matt: I'm not sure about your information and I certainly don't intend any offense in questioning your wiring instructions - but whilst you are correct in asserting that the high-end camera module gets its reverse signal from the CAN bus, I suspect that the 7th wire (Yellow?) is still needed because it tells the camera module to switch-off when the hatch lid is open.
Here's my very simplified wiring diagram for a high-line camera (note: the wire colors are not the same as your after-market module)
Notice that pin#6 on the 8 x pin connector (this is the meaning of "T8" on my diagram) on the camera module (labelled "SIG") is connected to the rear-lid contact switch. As I said, I suspect that this is the mysterious 7th wire in your discussion with OP!
For clarity "J794" in my diagram is VW's name for the MIB (i.e. the module that lives @ address hex5F).
Don