2017 F15 no SiriusXM or SOS

[HolyCityF15]

2017 F15 X5 sDrive35i

Two persistent issues I'm having are SiriusXM just has static and I have an SOS
emergency call malfunction. I have no other issues with iDrive, music, navigation, etc.

The front panoramic roof drain was previously clogged and water came in through the center where the roof switch panel is. I replaced the roof switch assembly and cleared codes, but the SOS emergency call malfunction keeps coming back.

I have the following two persistent codes:

Emergency Caller
B7F338: Airbag alive signal missing

Radio System
B7F8B5: Connection between head unit and SDARS antenna: Short circuit

I think the first code for the emergency caller might be the telematics battery in the white box under the sharkfin antenna. Is the telematics battery imperative to use a genuine BMW part, or are aftermarket batteries acceptable for this?

Could that also be the issue with the SDARS antenna connection? Could I need to replace the telematics box itself? Would the sharkfin antenna be a more likely culprit? I do NOT and have never had any water in the rear compartment.

Any pointers would be greatly appreciated!