All thank you for your comments and Merry Christmas! Wanted to follow up on some additional troubleshooting from yesterday.

1) through INPA, I verified the handbrake functions correctly, this isn't the issue.

2) completed the replacement of the front right (passenger) wheel speed sensor which occasionally threw a plausibility error, but as pointed out earlier in the thread the "brake" light in the gauge cluster was illuminated as "red" and not "yellow". Red typically means ABS module issues and yellow typically means wheel speed sensor issues. As an aside, it was a giant pain replacing the abs sensor. The original sensor was stuck in the hub and so brittle it disintegrated at both the connection to the car's wiring harness and broke off in the hub. Luckily I had a new pigtail connector on hand to replace where the ABS sensor hooks into the car's harness. Then after very carefully drilling out the old ABS sensor, cleaning the hub / magnetic ring, reinstalling the new Febi ABS sensor, I was able to rule out any wheel speed sensor issue. To aid in the troubleshooting I turned the X5 on without plugging in the abs sensor and immediately the Trifecta (with yellow brake light) appeared in the cluster. Makes sense since that's how it should be. I then plugged in the connector, put the wheel back on, lowered the car, and went for a test drive (After clearing the DSC codes). Upon starting the car before setting off, no Trifecta lights, but after putting the car into gear, the Trifecta (with red brake light) appeared.

3) checking the DSC codes once again return the inlet valve error, but no wheel speed errors (and I verified all wheel speed sensors report the same values when moving)

I will check the brake pressure sensor, but I'm pretty sure all signs point to the module at this point - especially thanks to the stubborn inlet valve error. Any other suggestions before I give in and order either a rebuilt or new abs module?

Thanks!